Williams was an excellent ballplayer as a child and later led his high school team to the state championships. He batted left-handed but threw right-handed, baseball's most desirable combination. Williams was signed by a minor league team in the Pacific Coast League, and after several seasons in San Diego and Minneapolis he was brought up to the Red Sox major league team in 1939. He had a fine rookie season with a batting average of .327.

His sophomore season in 1940 was more difficult. Although he batted .344 for the year, he was in something of a hitting slump in the early months. The criticism and heckling that arose from the sporting press and the fans soured Williams's attitude; thus began a career-long feud between Williams and the media and a love-hate relationship with Boston fans. Williams began refusing to acknowledge cheering fans—for the rest of his career he would never again tip his cap to the crowd.

In 1941 Williams hit for a season average of .406. His battle with the media continued, however. He had requested a draft deferment in 1942 because he was his mother's sole support. Many other players played baseball instead of enlisting in 1942 (Joe DiMaggio (DiMaggio, Joe), for example), but the press called Williams's choice unpatriotic and derided him for it. He decided to enlist in the U.S. Navy and entered active duty in November 1942. In that same year he won the first of two Triple Crowns (in which a player has the best batting average, most home runs, and most runs batted in 【RBIs】 during a single season).

Williams missed the baseball seasons of 1943–45 training and serving as a Navy flyer, but he saw no combat. Upon his return to baseball in 1946 he had lost none of his skill, hitting .342 in 1946 and in 1947 winning his second Triple Crown. In 1952 he was once again called up for military service, and for most of the '52 and '53 seasons he served as a pilot during the Korean War, this time in combat. (He batted .400 and .407 respectively for these years, but because he played only 43 games the records are not for complete seasons and therefore are not counted.)

Williams hit a career total of 521 home runs, even though he lost five prime years of his career to military service. He won the American League batting title in 1958 (at age 40) with a .328 average, the oldest player ever to do so. Concerning his abilities as a hitter, Williams once said, “A man has to have goals—for a day, for a lifetime—and that was mine, to have people say, ‘There goes Ted Williams, the greatest hitter who ever lived.'” In 1960 he announced that he would retire at the end of the year. During the final home game of the season he hit a home run in his last at bat. The fans cheered and called for him but Williams still refused to come out of the dugout and recognize them.

Williams returned to the major leagues from retirement in 1969 to manage the Washington Senators, and in his first year he was named American League Manager of the Year. He left the franchise in 1972, after it had become the Texas Rangers. After his retirement as a manager, he occasionally worked as a batting coach and became a consultant for a line of fishing equipment (he was an avid fisherman).

Williams was elected to the Baseball Hall of Fame in 1966. His autobiography, written with John Underwood, My Turn at Bat, was published in 1969. Other works written by Williams and Underwood are The Science of Hitting (1971) and Ted Williams' Fishing “The Big Three”: Tarpon, Bonefish, and Atlantic Salmon (1988). In 1991, to commemorate his .400 season, the Boston Red Sox hosted a Ted Williams Day. After a brief speech, Williams tipped his cap to the cheering Boston fans.