He played college football for the Kansas State Wildcats and was selected by the Patriots in the fifth round of the 1975 NFL draft.

While he showed moments of brilliance, and continued to be a fan favorite for his tenacious style of play, he only had one season during the rest of his career, 1983, when he started more than half of his team's games, and spent the majority of the rest of his career splitting starting time with a number of other quarterbacks.

He played in Super Bowl XX, coming off the bench to throw a pass for the only touchdown the Patriots scored on the day.

He was inducted into the New England Patriots Hall of Fame in 1995, and currently owns a sporting goods store in Massachusetts.

[4] Grogan spent his collegiate career at Kansas State University, where he started as a quarterback for his junior and senior years.

Grogan scored 12 rushing touchdowns in 1976, breaking a quarterback record of 11 previously held by Tobin Rote and Johnny Lujack.

[12] During the 1977 season, Grogan would continue to advance the ball with his legs, amassing another 300+ yard rushing season, though he would only find the end zone once on a running play, as running backs Horace Ivory, Sam "Bam" Cunningham and Andy Johnson did most of the scoring on the ground.

[5] The Patriots struggled defensively and could not hold on to leads provided to them by Grogan, and finished with a disappointing 9–7 record, missing the playoffs.

In the early 1980s, Grogan suffered several injuries,[7] and split starting duties on-and-off with Matt Cavanaugh.

The Patriots won 6 straight games behind their old quarterback, only to lose Grogan when he suffered a broken leg in Week 12 against the New York Jets.

[16] Filling in again at QB, Eason and the Patriots lost that Jets game 16–13 in overtime, and relinquished first place in the AFC East Division.

For the rest of the 1980s, the team became a revolving door of starting quarterbacks, as Grogan battled for playing time not only with Eason, but also with backup Tom Ramsey, local hero and fan favorite Doug Flutie, and journeyman Marc Wilson.

The Patriots struggled to remain above .500 for the final four years of his career, culminating in the disastrous and controversial 1–15 campaign of 1990, after which Grogan retired.

"[23] After retiring from the Patriots, Grogan attempted to get a coaching job, but found that no one above the high school level would hire him (except for the New England Blitz of the Professional Spring Football League, which announced Grogan as their head coach in 1992, but folded before playing a game).

Besides running the sporting goods shop, he also makes appearances at other local businesses and civic organizations.