Adams played college football for Utah State from 1970 through 1972 prior to becoming a professional athlete. During his time with the Utah State Aggies, Adams was the starting quarterback. The Aggies' 3-year record during Adams' tenure totaled up to 21 wins, 11 losses, and 1 tie. He didn't miss any games, playing in all 33 contests while he attended Utah State. On November 11, 1972, Adams set an NCAA record with 561 net passing yards and five touchdowns in a 44-16 Aggie win over the University of Utah Utes. The teams combined for an NCAA record 950 passing yards, and Adams 561 net passing yard stood for many years as an NCAA Division 1 record. The head coach that worked with Adams for all 3 seasons was Chuck Mills. His number 11 jersey was retired by Utah State in 1972.
His first actual professional season began with the Southern California Sun in the WFL in 1974, where he statistically had his best pro season, completing 276 of 510 passes for 3905 yards and 23 TDs and 18 interceptions. He was an All-WFL selection that season. He was also named one of the WFL's Tri-MVP's during the 1974 season. He shared this award with Tommy Reamon of the Florida Blazers and J.J. Jennings of the Memphis Southmen. Adams led the Sun to a 13-7 record and the team won the 1974 WFL Western Division. They faced the Hawaiians in the opening round of the '74 WFL playoffs and fell by a score of 32-14.
Adams began his career in the NFL in 1975 with the Kansas City Chiefs. During his 4-year stint with the Chiefs, he appeared in 50 games, 7 of them as the starting quarterback. He was never able to reach the success that he had in the WFL, winning only 1 of the 7 games that he started. He completed 163 of 319 passing attempts for 2,126 yards, 9 TDs, and 22 interceptions. Adams would no longer be a member of the Chiefs after the 1978 season.
Adams then went on to play 20 games over two seasons (1979–1980) for the Toronto Argonauts of the CFL, his best year being 1979, when he hit 241 of 394 passes for 2,692 yards and 13 TDs and 18 interceptions.
He finished his career as a strikereplacement player with the Minnesota Vikings in 1987. By this time, Adams was already 37 years old, and this stint with the Vikings didn't do much to revive his career. This was the first playing time he saw since playing in his last season in the CFL in 1980. He started in all 3 games that he played in for the Vikings, losing all 3 of those games. He completed 49 of his 89 pass attempts for 607 yards while posting 3 Tds and 5 interceptions.