version of the sport of football so named for the vertical yard lines marking the rectangular field. Gridiron football evolved from English rugby and soccer (association football); it differs from soccer (football (soccer)) chiefly in allowing players to touch, throw, and carry the ball with their hands, and it differs from rugby in allowing each side to control the ball in alternating possessions. The sport, played with 11 on each side, originated in the United States, where it was largely developed and eventually became the country's leading spectator sport. It quickly spread to Canada (where it evolved into a 12-man game), though it never achieved the great popularity and status of ice hockey there. Gridiron football has not been taken up in the rest of the world to the same degree as other American sports such as basketball and baseball. Since the 1980s, however, primarily through the marketing efforts of the National Football League, teams and leagues have been established in Europe, and the game has achieved a degree of international popularity through television.

Harvard made the first breach in rugby rules. Rejecting the traditional manner of putting the ball in play—players from both teams massed about the ball in a “scrummage,” or “scrum,” trying to kick it forward through the mass of players—Harvard opted for “heeling it out,” or kicking the ball backward to a teammate. The further transformation of English rugby into American football came chiefly through the efforts of Walter Camp (Camp, Walter), who even during his lifetime was known as the “Father of American Football.” As an undergraduate and then a medical student at Yale, Camp played football from 1876 through 1881, but—more important—beginning in 1878, he dominated the rules committee for nearly three crucial decades. Two of Camp's revisions in particular effectively created the gridiron game. The first, in 1880, further refined Harvard's initial innovation, abolishing the scrummage altogether in favour of a scrimmage, which awarded possession of the ball to one of the two teams. It was then put in play by heeling it out. (Snapping the ball with the hand became legal in 1890, though snapping with the foot continued as an option until 1913.) The second crucial rule change was necessitated by the first. Camp's more orderly manner of initiating play did not require the team in possession of the ball to give it up. After Princeton simply held the ball for an entire half in its 1880 and 1881 contests with Yale, both games ending in scoreless ties that bored spectators as much as they frustrated Yale's players, Camp proposed a rule that a team must advance the ball 5 yards or lose 10 in three downs (plays), or it would be obliged to surrender the ball to the other side. Camp was also responsible for having 11 players on a side, for devising a new scoring system in 1883 with two points for a touchdown, four points for the goal after a touchdown, and five points for a field goal (a field goal became worth three points in 1909, a touchdown six points in 1912), for naming the positions (centre, guard, tackle, end, quarterback, halfback, fullback), for marking the field with stripes, and for proposing several other innovations; but it was those two simple rules adopted in 1880 and 1882 that most fundamentally created American football.

In 1879 the University of Michigan (Michigan, University of) and Racine College of Wisconsin inaugurated football in the Midwest. Michigan under Fielding Yost (Yost, Fielding) in 1901–05 and the University of Chicago (Chicago, University of) under Amos Alonzo Stagg (Stagg, Amos Alonzo) in 1905–09 emerged as major powers. The game also spread throughout the rest of the country by the 1890s, though the Big Three—Harvard, Yale, and Princeton—continued to dominate the collegiate football world into the 1920s. Ever mindful of their superiority to the latecomers, the three (joined by the University of Pennsylvania to create briefly a Big Four) formed the Intercollegiate Rules Committee in 1894, separate from the Intercollegiate Football Association. In 1895 in the Midwest, colleges dissatisfied with this divided leadership asserted their independence by forming what became the Western (now the Big Ten (Big Ten Conference)) Conference. The game also spread to the South and West, though conferences were not formed until later in those regions.

The 1920s saw the emergence of Red Grange (Grange, Red) as football's first true celebrity. Grange received national acclaim for his brilliant performances in games against Michigan and Pennsylvania, but he also created the sport's greatest controversy since the 1906 rule changes when he left the University of Illinois (without graduating) to join the Chicago Bears of the professional National Football League. “Professionalism” in any form—the paying of coaches, the recruiting and subsidizing of athletes, the commercializing of the supposedly amateur game—violated the sport's purported principles, yet it was also at the heart of the popular spectacle staged in the enormous stadiums before as many as 120,000 spectators. College football was regularly attacked in intellectual journals, but the routine celebration of the game in the daily and weekly coverage of the popular media drowned out any criticism. A report by the Carnegie Foundation in 1929 documenting professionalism at 84 of 112 institutions troubled many college administrators but was generally shrugged off by the public and the sportswriters who fed its passion for the game.

A distinguishing mark of American football is the renown and status granted to the most successful and innovative coaches. The first innovators were men such as Walter Camp (not literally a coach but an adviser), Amos Alonzo Stagg (Stagg, Amos Alonzo) at the University of Chicago, George Woodruff at Pennsylvania, and Lorin Deland at Harvard, the coaches who developed the V trick, ends back, tackles back, guards back, flying wedge, and other mass formations that revolutionized, and nearly destroyed, the game in the 1890s. The most influential of the early coaches was Pop Warner (Warner, Pop), whose wingback formations (the single wing and the double wing), developed at Carlisle, Pittsburgh, and Stanford, became the dominant offensive systems through the 1930s.

As college football thrived, professional football struggled for respectability. The group of teams that became the National Football League (NFL) was organized in 1920 as the American Professional Football Association (changing its name in 1922), with Jim Thorpe (Thorpe, Jim) as its nominal president. Former (and sometimes current) college stars had played for money since 1892, initially for athletic clubs in western Pennsylvania, then for the openly professional teams that were formed in mostly small towns in Pennsylvania, Ohio, and Illinois. In its first season, in 1920, the APFA had 14 teams, including George Halas (Halas, George)'s Decatur (Illinois) Staleys, who in 1922 became the Chicago Bears, the NFL's dominant team for much of its formative period. Joe Carr, an experienced promoter, succeeded Thorpe as president in 1921 and remained in that position until his death in 1939. Over the 1920s and early 1930s, league membership fluctuated between 8 and 22 teams, the majority not in large cities but in towns such as Akron, Canton, Dayton, and Massillon, all in Ohio; Racine, Wisconsin; and Rockford, Illinois. With professionalism widely regarded as the greatest danger to college football, professional football was little more respectable than professional wrestling. Red Granges' turning professional in 1925 provided a temporary boost to the professional game, but interest in professional football could be sustained only in those communities with franchises.

The NFL took its modern shape in 1933 under Carr's guidance, when it was reorganized in two five-team divisions of big-city clubs (with Green Bay the lone exception) whose leaders would meet at the end of the season for the NFL title. In the 1930s professional football was predominantly a working-class spectator sport. The preseason College All-Star Game, created by Chicago Tribune sports columnist Arch Ward in 1934 to pit the reigning NFL champion against a team of just-graduated collegians, helped break down the barrier between college and professional football. Over the 1930s and '40s the professional sport's popularity grew in NFL cities, particularly those such as New York without a major state university with which to compete for the community's loyalty. Minor professional leagues such as the American Association, Dixie League, and Pacific Coast Professional Football League had relatively modest local followings. The NFL was also successful enough to attract competitors. The American Football League was formed in 1926 by Grange and his agent, but it lasted just one year. A second (1936–37) and third (1940–41) AFL were also formed. Finally, the All-America Football Conference (1946–1949) seriously challenged the existing league and contributed the Cleveland Browns, San Francisco 49ers, and a first version of the Baltimore Colts (Indianapolis Colts) to an expanded NFL in 1950. Yet professional football could offer the public nothing comparable to the compelling rivalries, youthful enthusiasm, and colourful pageantry of college football. It was only in the 1950s with the arrival of television that professional football could reach beyond the franchise cities to become a national sport.

Mainstream football, however, was not altogether segregated (segregation, racial). William Henry Lewis and William Tecumseh Sherman Jackson were black teammates for Amherst College in 1889, and Lewis made Walter Camp's All-America team in 1892 after he had moved to Harvard to play football while attending law school (he later became an assistant U.S. attorney general). A handful of black players were always part of big-time college football, and some—including Lewis, Fritz Pollard (Pollard, Fritz) at Brown, Paul Robeson (Robeson, Paul) at Rutgers, and Duke Slater at Iowa—were among the early game's greatest stars. Yet, until 1939, when UCLA fielded a team that included Jackie Robinson (Robinson, Jackie), Kenny Washington (Washington, Kenny), and two other black teammates, no college had more than one or two black players, and most continued to have none.

The NFL had been integrated at the beginning, with Fritz Pollard among the league's first stars and some 13 African American players hired between 1920 and 1933. Between 1934 and 1945, however, a “gentleman's agreement,” apparently at the instigation of George Preston Marshall, owner of the Boston (later Washington) Redskins (Washington Redskins), kept the NFL all-white. The reintegration of professional football began in 1946—in the NFL, where the Rams risked losing their lease on the Los Angeles Coliseum if they did not sign Kenny Washington (the Rams signed Woody Strode as well, to give Washington a black roommate); and in the rival All-America Football Conference, where coach Paul Brown (Brown, Paul) immediately signed Bill Willis and Marion Motley (Motley, Marion) for his Cleveland Browns—and it was completed in 1962, when Marshall signed Bobby Mitchell to play for the Redskins. The first generation of black NFL stars came almost exclusively from the mainstream football world, but in the 1960s NFL scouts discovered the black colleges, Eddie Robinson (Robinson, Eddie)'s Grambling Tigers in particular. This golden era for black college football was short-lived, however, as integration ended the black colleges' monopoly on local African American athletic talent.

Even as bowl games proliferated in the 1930s, '40s, and '50s, controversies shadowed them—for their commercialization of the amateur sport and prolonging of the season at the expense of academics—but resistance disappeared when the financial windfall from the televised contests became a major source of revenue for the top teams and conferences. A new controversy emerged in the 1970s, however, regarding the bowls' inability to produce an unambiguous national champion. A perennial call for a national championship playoff, resisted by defenders of the traditional bowl games, eventually prompted the creation in 1992 of the Bowl Coalition—involving four major bowl games (Cotton, Fiesta (Fiesta Bowl), Orange, and Sugar), five major conferences (excluding the Big Ten and Pac-10), and independent Notre Dame—with the goal of matching the two top-rated teams in a championship game that would rotate among the four bowls. In 1995 the Bowl Coalition was replaced by the Bowl Alliance (involving six conferences, Notre Dame, and only three bowls), but the nonparticipation of the Rose Bowl, Big Ten, and Pac-10 continued to leave the scheme badly flawed. In 1998 the Rose Bowl and its two participating conferences joined the Bowl Championship Series (BCS) (BCS), which included all the major teams and conferences, with a supposed national championship game now rotating among the Rose, Orange, Sugar, and Fiesta bowls. The matching of the University of Nebraska with Miami in the 2002 Rose Bowl, however, after Nebraska had failed to win its own conference championship, made it clear that the BCS had not yet resolved the issue and guaranteed that a debate over a playoff along the lines of the NCAA basketball tournament would continue.

The NFL faced competition from a new rival in 1960, when the American Football League (AFL), backed by Texas billionaire Lamar Hunt, fielded teams in eight cities, three of them in direct competition with NFL franchises. A television contract with NBC gave the AFL a financial security none of its predecessors had had, and the NFL and AFL agreed to a merger in 1966, completed in 1970 with 26 clubs in two conferences. The pass-oriented AFL brought more excitement to professional football, as well as the game's most glamorous player, the New York Jets' quarterback Joe Namath (Namath, Joe). Out of the merger also came the Super Bowl, which soon became the single most popular and lucrative of all sporting events in the United States. Super Bowl I (not yet with that name) was played between the Green Bay Packers and the Kansas City Chiefs after the 1966 season, with more than 40 percent of the country's television sets tuned in to the two networks that broadcast the game. That percentage never dropped lower than 36, and it nearly hit 50 in 1982, as the game was eventually watched by as many as 130 million Americans in addition to a worldwide audience. The Super Bowl became a major civic ritual, as famous for its surrounding hoopla and million-dollar commercials as for the football games.

The original defenses had simply mirrored the positions of the offense. In the 1930s a 6-2-2-1 alignment became dominant (6 linemen, 2 linebackers, 2 cornerbacks, and 1 safety). In the NFL, to stop the increased passing that came with the T formation in the 1940s, the Philadelphia Eagles' Greasy Neale developed the 5-3-2-1 defense, which was in turn replaced in the mid-1950s by the 4-3 (actually 4-3-2-2) perfected by Tom Landry (Landry, Tom) as an assistant coach with the New York Giants. In this alignment the defensive tackles kept blockers off the middle linebacker, who became the dominant defensive player. The 4-3 defense made stars of such middle linebackers as Sam Huff, Joe Schmidt, Ray Nitschke, Dick Butkus (Butkus, Dick), and Willie Lanier (Lanier, Willie). The 4-3, in turn, yielded to the 3-4 in the mid-1970s, moving the emphasis to outside linebackers rather than the middle linebacker. The New York Giants' Lawrence Taylor (Taylor, Lawrence) became the prototype outside linebacker in the 1980s, with tremendous speed to cover receivers and tremendous power to rush the quarterback.

Pass defenses had always been either man-to-man or zone (each back covering an area). In the 1970s, when zone defenses virtually eliminated long passes, strong running games—featuring backs such as Buffalo's O.J. Simpson (Simpson, O.J.), Miami's Larry Csonka and Jim Kiick, and Pittsburgh's Franco Harris and Rocky Bleir—dominated the NFL. Landmark rule changes in 1977—banning defensive contact with wide receivers more than five yards downfield and allowing offensive linemen to block with their open hands—returned the advantage to the passing offenses. Small, quick offensive linemen gradually disappeared, replaced by 300-pound (140-kg) hulks who could hold off charging pass rushers with their extended arms and hands. (There were eight 300-pounders in the NFL in 1986 and 179 in 1996). Led by the so-called West Coast offense developed by Bill Walsh (Walsh, Bill) for the San Francisco 49ers, the passing game flourished as never before (in 1980 there were more passing than running plays for the first time since 1969). Other coaches developed run-and-shoot offenses, no-huddle offenses, and one-back offenses (with four wide receivers and no tight ends). Defensive coaches responded with “combo” pass defenses (combinations of zone and man-to-man), and the cornerback who could dominate a wide receiver by himself (Deion Sanders became the prototype) emerged as a new star. Running attacks increasingly featured a single back, making stars of such players as Tony Dorsett, Eric Dickerson, Walter Payton (Payton, Walter), Barry Sanders (Sanders, Barry), and Emmitt Smith (Smith, Emmitt).

The gridiron football played in Canada closely resembles the U.S. game, but it developed independently, and, overshadowed by ice hockey, it never achieved equal national importance.

Then came precipitous decline and turmoil. Faced with competition from televised NFL games and a persistent perception that home-grown football was second-rate, the CFL saw TV revenues fall to $240,000 per club by 1991. Montreal lost its original franchise in 1982, then its replacement in 1987. Deficit-burdened franchises did not move but repeatedly changed hands. The purchase of the Toronto Argonauts in 1991 by millionaire Bruce McNall, actor John Candy, and hockey great Wayne Gretzky (Gretzky, Wayne) marked the most conspicuous effort to produce first-class football with highly paid U.S. stars, but the experiment failed, and McNall and Gretzky sold the club in 1994 after Candy died. Constantly fearing NFL expansion into Montreal and Toronto, CFL leaders had been discussing since the early 1970s their own expansion into the United States, which became a reality with teams in Sacramento (California) in 1993 and Las Vegas (Nevada), Shreveport (Louisiana), and Baltimore (Maryland) in 1994, but the experiment failed after just three seasons. In 1996 the CFL reverted to an eight-team all-Canadian league, then returned to its original nine for the 2002 season as the league continued to face an uncertain future.

The field for U.S. gridiron football is 120 yards (109.8 metres) long (including two 10-yard 【9.1-metre】 end zones) and 53.33 yards (48.8 metres) wide. A coin toss at the beginning of the game determines who will put the ball in play with a place kick from the 30-, 35-, or 40-yard line (at the professional, intercollegiate, and scholastic levels, respectively) and which goal each team will defend. Following the kickoff, the centre of the team in possession of the ball puts it in play by passing it between his legs to the quarterback, who hands it off to another back, passes it to a receiver, or runs it himself. Opponents try to stop any advance toward their goal line by tackling the runner or by batting down or intercepting passes. The offensive team earns a "first down" by advancing the ball 10 yards in four downs or fewer and can retain the ball with repeated first downs until it scores or until the defense gains possession of the ball by recovering a fumble or intercepting a pass. Failing to make a first down, the offensive side must surrender the ball, usually by punting (kicking) it on fourth down. The offense scores by advancing the ball across the opponent's goal line (a six-point touchdown) or placekicking it over the crossbar and between the goal posts (a three-point field goal). After a touchdown, the ball is placed on the three-yard line (the two-yard line in the NFL), and the scoring team is allowed to attempt a conversion: a placekick through the goal posts for one point or a run or completed pass across the goal line for two points. The defense can score by returning a fumbled football or an interception across the other team's goal line for a touchdown, by tackling the ball carrier behind his own goal line (for a two-point safety), or by returning a failed conversion attempt across the opponent's goal line (two points). Another kickoff, by the scoring team, follows each score, and the same pattern is repeated until playing time for the half expires (30 minutes for intercollegiate and professional football, 24 minutes for scholastic). After an intermission of 15 or 20 minutes, a second half follows, with the team that lost the initial coin toss choosing to kick or receive. The team that has scored the most points by the end of the game is the winner, and tie games are settled by additional play, determined by varying rules at the different levels.

Super Bowl Super BowlSuper Bowl results are provided in the table.

College football national champions College football national championsA chronological list of college football national champions is provided in the table.

Grey Cup Grey CupGrey Cup results are provided in the table.

The most comprehensive history of the U.S. intercollegiate game is John Sayle Watterson, College Football: History, Spectacle, Controversy (2000). Michael Oriard, Reading Football: How the Popular Press Created an American Spectacle (1993), and King Football: Sport and Spectacle in the Golden Age of Radio & Newsreels, Movies & Magazines, the Weekly & the Daily Press (2001); Murray Sperber, Shake Down the Thunder: The Creation of Notre Dame Football (1993, reissued 2002), and Onward to Victory: The Crises That Shaped College Sports (1998); David M. Nelson, The Anatomy of a Game: Football, the Rules, and the Men Who Made the Game (1994); and Robin Lester, Stagg's University: The Rise, Decline, and Fall of Big-Time Football at Chicago (1995), also are authoritative treatments of aspects of the game. The NCAA publishes useful annuals.For U.S. professional football, the most authoritative source is Bob Carroll, Michael Gersham, David Neft, and John Thorn (eds.), Total Football: The Official Encyclopedia of the National Football League, rev. and updated ed. (1999; also published as Total Football II). Robert W. Peterson, Pigskin: The Early Years of Pro Football (1997), provides a narrative history of the NFL's pretelevision era. The Sporting News Pro Football Guide is published annually.Racial aspects are documented in Arthur R. Ashe, Jr., A Hard Road to Glory—Football: The African-American Athlete in Football (1993); Michael Hurd, Black College Football, 1892–1992: One Hundred Years of History, Education and Pride, rev., expanded 2nd ed. (1998); and Charles K. Ross, Outside the Lines: African Americans and the Integration of the National Football League (1999).The most reliable histories of Canadian football are Frank Cosentino, Canadian Football: The Grey Cup Years (1969), and A Passing Game: A History of the CFL (1995). Current information can be found in the Canadian Football League annual, Facts, Figures and Records.Michael Oriard