As a freshman at the University of Georgia, Walker was All-America, Southeastern Conference player of the year and led his team to the national championship. By the time he was a junior he had three SEC player-of-the-year trophies, a coveted Heisman Trophy, held 80 NCAA, SEC, and Georgia records, and was ranked with the greatest runners ever.
In 1983, he skipped his senior year to turn professional and immediately became the greatest player in league history, recording 11 consecutive 100-yard games. That league, however, was the United States Football League, not the NFL.
When the USFL folded after three years, Walker joined the Dallas Cowboys. He responded with solid seasons in 1986 and 1987, but in 1988 he showed the form that had been predicted. He gained 1,514 yards rushing and earned 505 yards as a receiver.
The moribund Cowboys could have built the team around Walker, but they decided to use him to rebuild the team instead. In one of the most famous - or infamous - trades in NFL history, the Cowboys sent Walker to the Minnesota Vikings in the largest trade ever (18 players or draft picks were involved). The Cowboys won back-to-back Super Bowls in five years; in Minnesota, Walker was stuck in an offensive system unsuited to his talents. After three disappointing seasons with the Vikings, he signed with Philadelphia, where he surpassed 1,000 yards rushing in 1992.
Walker was an extremely talented all-around athlete; he has a sixth-degree black belt in tae kwon do and he nearly made the Olympic team in the sprint relay. He ran the 100 meters in 10.22, the 100 yards in 9.3. He competed in the 1992 Winter Olympics in two-man bobsled, finishing seventh. He also won back-to-back American Superstars competitions in 1987 and 1988. Walker stated in a phone interview on The Jim Rome Show on November 20, 2006 that he still performs 2,500 sit-ups and 1,500 push ups every morning. He has been going through this same routine every morning since high school.
In November 2007, Walker appeared on the HDNet show Inside MMA as a guest. He indicated that he would take part in a mixed martial arts reality show in the near future (along with Josť Canseco) and that he would have an official MMA fight at the conclusion of the show.
He is a born-again Christian who frequently talked about his faith during his USFL interviews. Since his retirement he has attracted little publicity, although he made a guest appearance on The Hour of Power, hosted by noted televangelist Robert Schuller.
In his autobiography entitled "Breaking Free", published in 2008, Walker revealed that he suffers from dissociative identity disorder, or DID, formerly known as "multiple personality disorder." He has revealed that due to his social disorder, he can not remember the season he won the Heisman Trophy, let alone the moment. He also revealed that during an episode, he had held a gun to his ex-wife's head. He stated he did not ever remember doing this. He is getting help for this disorder, and feels he has turned it around.
In an interview with CNN in April 2008, he revealed he has played Russian Roulette several times.