He won a close race over Buffalo Bills linebacker Kiko Alonso for the honor. Richardson received 23 votes from a nationwide panel of 50 media members that regularly covers the league. Alonso, a second-round choice (46th overall), got 19 in balloting announced Saturday night.
Richardson became the first Jets player to win the award since linebacker Jonathan Vilma in 2004.
For the first time since 2004, a San Diego Chargers quarterback won the league's Comeback Player of the Year award.
Philip Rivers' turnaround season earned him the honor as he led the Chargers to a wild-card playoff spot with four straight victories to close out the schedule, giving them a 9-7 record. He led the league with a 69.5 completion percentage and threw for 32 TDs against 11 interceptions.
Drew Brees, the man Rivers replaced, was the Chargers' '04 winner.
Ron Rivera took the Carolina Panthers from also-ran to division champion this season, earning him the Coach of the Year award.
Rivera's Panthers went 12-4 to take the NFC South and get a first-round playoff bye. They lost to San Francisco in the divisional round.
Rivera's fine work in his third season in charge in Carolina brought him 21½ votes from a nationwide panel of 50 media members who regularly cover the league in balloting announced Saturday night. That outdistanced Kansas City's Andy Reid, who got 13½ votes after his first season with the Chiefs.
Information from ESPN.com Jets reporter Rich Cimini and the Associated Press contributed to this report.