American professional National Football League (NFL) middle linebacker for the Chicago Bears who was the dominant defensive player of his era. He was large for a middle linebacker (6.25 feet 【1.9 metres】 and 245 pounds 【111 kg】) and had a reputation for relentless pursuit and ferocious tackling.

Butkus played gridiron football as a fullback and linebacker at Chicago Vocational High School. At the University of Illinois, he played middle linebacker (1962–64), earning All-America honours in 1963 and 1964. He also starred in the 1963 Rose Bowl game, a 17–7 Illinois victory over the University of Washington.

In his first year with the Bears (1965), Butkus intercepted five passes, and in 1970 NFL coaches voted him the player whom they would most like to have on their teams. In a career shortened by injuries, Butkus accumulated 1,020 tackles, 22 interceptions, and 25 fumble recoveries. After retiring in 1973, he was active in television and films. He was elected to the Pro Football Hall of Fame in 1979.

Since 1985 the Downtown Athletic Club of Orlando (Florida) has awarded the Butkus Trophy to the outstanding collegiate linebacker of the year.