- Cleveland Browns (1975 - 1977)
- Toronto Argonauts (1979 )
- Cincinnati Bengals (1980 - 1983)
- Green Bay Packers (1984 - 1987)
- SMU Mustangs (1989-1990)
- Shreveport Pirates (1994 - 1995)
- 9 × Pro Bowl selection (1959, 1960, 1961, 1962, 1963, 1964, 1966, 1967, 1968)
- 8 × All-Pro selection (1959, 1960, 1962-1967 )
- 5 × NFL Championship (1961, 1962, 1965-1967 )
- NFC Champion (1970 )
- AFC Champion (1981 ) as a trainer
- 3 × Super Bowl champion (I, II, V)
- NFL 75th Anniversary All- Time Team
- NFL 1960s All- Decade Team
- NFL Coach of the Year (1976 )
- Texas Sports Hall of Fame
- Pro Football Hall of Fame (1977 )
Gregg played at the SMU Mustangs of the team from Southern Methodist University as a tackle both on offense, as well as in Defense. Gregg was with 113 pounds of body mass for this position slightly resembled but this disadvantage with speed and agility from. During his career in college his team was able to move in no Bowl game. Nevertheless, the NFL scouts were aware of him.
1956 Gregg was taken in the NFL Draft by the Green Bay Packers in the second round in 20th place. Gregg, who was actually committed as defender came mainly in attack used. 1956 committed the Packers also their later starting quarterback Bart Starr, whose protection was one of Gregg's future main tasks in the attack. A year later, the running back Paul Hornung joined the Packers in 1959 took over the legendary Vince Lombardi, the Office of Head coach in Green Bay. The Packers were one of the best football teams of the time. They developed specifically for Forrest Gregg moves to exploit useful to its superior speed and agility.
Gregg, who prepared by intense film studies at his opponent, has developed into a key player of his team. Due to injury, came Gregg 1961-1965 also on the position of a Guards used. But also proved itself on this unfamiliar position for him.
The Packers celebrated with Gregg numerous successes, she won a total of five times the NFL Championship. 1961 and 1962 against the New York Giants quarterback YA Tittle with 37:0 and 16:7 with 1965 against the Cleveland Browns at 23:12, 1966 and 1967 respectively against the coached by Tom Landry Dallas Cowboys with 34:27 and 21: 17 The latter game went down in the history of the NFL as the Ice Bowl. Both games against the Cowboys meant a place in the AFL- NFL Championship Game ( later renamed the Super Bowl). 1967 could be beaten in the Super Bowl I, the Kansas City Chiefs at 35:10, a year later there was a victory against the Oakland Raiders at 33:14.
1970 Gregg wanted to put to rest the age of 37, but accepted an offer from the Cowboys, who were in search of players due to a number of injured players. He should not regret that decision and won with the team from Texas again a Super Bowl, Super Bowl V with 24:3 against the Miami Dolphins.
Gregg worked as head coach at three NFL teams. From 1975 to 1977 he coached the Cleveland Browns from 1980 to 1983, the Cincinnati Bengals from 1984 to 1987, he coached the Packers. His coaching career was not as successful as his playing career. Only in 1981 he was his Bengals, according to a 27:7 victory in a historically cold AFC Championship Game against San Diego Chargers lead in the Super Bowl XVI, but then had to give 49ers defeated cited by Joe Montana San Francisco with 26:21.
1979 Gregg was also for one year coach of the Toronto Argonauts in the Canadian Football League ( CFL), but was unsuccessful in Canada. 1989 to 1990 he coached his old college team, but lost 19 of 22 games with the team weakened by the Pony Gate scandal. From 1994 to 1995 he was again unsuccessful, held the coach of the Shreveport Pirates a former U.S. team in the CFL. Then Gregg finished his coaching career. He is currently Vice President of the Ottawa Renegades.
Gregg played nine times in a Pro Bowl, the final game of the best players of the season. In addition, he was elected nine times by the American press in the All Pro team. He is a member of the Pro Football Hall of Fame, the Texas Sports Hall of Fame, the National Football League 75th Anniversary All- Time Team and the National Football League 1960s All- Decade Team. In 1976 he was elected to the NFL Coach of the Year. The magazine The Sporting News named him in 1999 as one of the best football players of all time.