Ferguson placed in the top 10 in pass attempts five times, completions and passing yards four times, passing touchdowns six times, and yards per pass three times. At one time he shared, with Ron Jaworski, the NFL record for consecutive starts by a quarterback with 107, until he was replaced by Joe Dufek on September 30, 1984. He has a 1-3 record in the NFL postseason, winning against the New York Jets in 1981. His three losses came from the Cincinnati Bengals in those same playoffs, the San Diego Chargers the year before in 1980 (a game in which he played the entire contest with a sprained ankle), and in 1974 to the Pittsburgh Steelers. He retired after the 1990 season after playing only one game with the Colts.
Ferguson's best season came in the 1975 campaign, when he tied Fran Tarkenton for the NFL lead with 25 touchdown passes and compiled a passer rating of 81.3. Ferguson also surpassed 20 touchdown passes on three other occasions (1980, 1981 & 1983).
Ferguson is one of few quarterbacks who started immediately as a rookie, and his team won four of his first six starts. He is one of only two rookie quarterbacks to accomplish this feat, being joined by the Atlanta Falcons' Matt Ryan in 2008.