Jennings spent 11 years with the Giants and was one of the better punters in franchise history. He made the Pro Bowl four times and was named to the All-Pro Team in 1979 and 1980. He later played for the New York Jets for three seasons before retiring in 1988.
After leaving the league, Jennings went into sports broadcasting. He was a color commentator for Jets games from 1988 to 2001, and later joined Bob Papa and Dick Lynch on WFAN from 2002-07. In addition to game analysis for Giants games, Jennings was part of the pre- and post-game shows, covering player interviews from the locker room. Jennings has been battling Parkinson's disease for nearly two decades up to his death, and left the broadcast booth in 2008.
He holds the Giants' franchise record for punting yards and was inducted into their Ring of Honor in 2011.