A former Purdue star, who led the Big 10 in passing and total offense for three seasons, Dawson was a number one draft pick of the Pittsburgh Steelers in 1957. He struggled through five seasons as a seldom-used backup with the Steelers and the Cleveland Browns before finding his niche with the Dallas Texans of the American Football League in 1962. Dawson led the Texans, who became the Kansas City Chiefs the next year, to AFL Championships in 1962, 1966 and 1969.

Noted for his calm approach to every situation, Dawson was often praised by his coach, Hank Stram, as "the most accurate passer in pro football." His record backs up that claim. Dawson won four AFL individual passing honors in 1962, 1964, 1966 and 1968 and still holds Chiefs career marks for pass rating, attempts, completions, passing yards and touchdowns.

He was selected to play in six AFL All-Star games and the 1972 AFC-NFC Pro Bowl. An All-AFL selection in both 1962 and 1966, he was named the AFL Player of the Year in 1962. During his career, he played in 211 games, completing 2,136 of 3,741 passes for 28,711 yards with 239 touchdowns and 183 interceptions, while rushing for 1,293 yards and nine scores on 294 carries.

Len was named the 1973 NFL Man of the Year and was inducted into the Pro Football Hall of Fame in 1987. In the same year, he was also named "Best Kansas City Sportscaster" by Kansas City Magazine. His jersey number (16) has been retired by the Chiefs. In 1994, he was inducted into the Missouri Sports Hall of Fame.

After 19 years, one of the longest careers in professional football history, Dawson retired in 1976. Since his retirement, he hosted HBO's Inside the NFL from 1976-2001 and currently serves as a television sports anchor in Kansas City and provides color analysis for regional radio broadcasts of Kansas City Chiefs' Games.

Later in life, Dawson came face-to-face with another opponent - prostate cancer. Since overcoming this life-threatening illness, he has become a spokesperson for the American Cancer Society. He is also highly active in community and charitable organizations dealing primarily with children. Len has been the Honorary Chairman of the Variety Club Telethon for several years and also hosts the Len Dawson Celebrity Golf Classic which benefits the Truman Medical Center.