Background and college
O'Brien lived in Brooklyn until his family moved to the West Coast when he was 3. He later played for Jesuit High School in Carmichael, California. O'Brien started his collegiate football career in 1978 at Sacramento State as a reserve. He played at the University of California, Davis under coach Jim Sochor. In his senior year, 1982, he was a Division II All-American. He led UCD to a 10-0 regular season mark and to the Division II championship game. He was ranked #2 in total offense and #3 in passing efficiency in Division II. He also won the Babe Slater Award for being the best offensive player in the Conference. He was selected as All-Far Western Conference QB three times and was selected to the College Football Hall of Fame in 1997.
As a Jet
O'Brien was taken by the Jets with the 24th pick of the first round in the 1983 NFL Draft, three picks before Dan Marino. O'Brien spent his first season sitting on the bench, but in 1984 he was named starting quarterback by head coach Joe Walton. In 1985, he led the NFL in passer rating, passed for almost 4,000 yards and was named to the Pro Bowl as he led the Jets to 11-5 and a playoff place. O'Brien wasn't the most mobile of quarterbacks, and in 1985, he set a then NFL record of being sacked 62 times.Wesley Walker) in a legendary 51-45 overtime win against the Miami Dolphins, quarterbacked by Dan Marino. Marino threw for 465 yards and 6 touchdowns. The combined 927 passing yards is an NFL record for opposing quarterbacks, and the 884 combined passing yards by the two teams(subtracting 43 yards on 5 sacks) is an NFL record. In overtime, O'Brien hit Walker with a 43-yard TD pass for the win. In fact, the Jets and Dolphins had more than a few high-scoring shootouts in the mid-to-late 80's with O'Brien and Marino leading the way.
1986 was another good season for O'Brien, throwing for over 3,500 yards and getting the Jets into the playoffs again. It was generally downhill after that, especially after the arrival of Bruce Coslet in 1990 but O'Brien did get the Jets to the playoffs in 1991 and was named to his second Pro Bowl. In 1992 O'Brien became embroiled in a contract dispute with the team and missed most of training camp as the Jets seemed loathe to show much interest in him or make him feel wanted. During O'Brien's absence, Browning Nagle won the starting job. When O'Brien came back he indicated that the Jets had deliberately stalled his contract negotiations to give Nagle a leg up on the starting job. The Jets denied the charge. Nagle struggled, and all too often was replaced by O'Brien. In 1993 Coslet then brought in Boomer Esiason and promptly gave O'Brien's No.7 jersey to Esiason. Shortly afterwards, O'Brien was traded to Green Bay for a draft pick.
After the Jets
He retired after spending the 1993 season with the Philadelphia Eagles.
Stats as a Jet
When O'Brien's football career ended, he returned to his hometown of Sacramento and became a sports broadcaster for two years. He also had a stint as an assistant coach for the University of Southern California, where he coached Heisman Trophy winner and current Cincinnati Bengal Carson Palmer.