| Defensive coordinator|| Towson Tigers football|
| (1978-10-26) October 26, 1978 (age 38)|
New York Jets (Coach), Buffalo Bills (Coach), Cleveland Browns (Defensive coordinator)
Mike Pettine, Chip Kelly, Hue Jackson, Rex Ryan, Jim O'Neill - Baron O'Neill of
Jim O'Neil is an American football coach who was most recently the defensive coordinator for the San Francisco 49ers of the National Football League (NFL). He held that position in 2016 and was fired after the season. He has previously been a coach in the NFL for the New York Jets, Buffalo Bills, and the Cleveland Browns. He was a coach for numerous college football teams before that.
From 2006-08, he was at Eastern Michigan as the recruiting coordinator and safeties coach. He was the defensive coordinator at Towson in 2005, a graduate assistant/defensive back coach at Northwestern from 2003–04, assistant offensive line coach at Pennsylvania in 2002 and an assistant offensive line/tight ends coach at SUNY Albany in 2001.
O'Neil entered the NFL joining the New York Jets as a defensive quality control & defensive backs coach in 2009. He was moved to assistant defensive backs coach in 2010 and remained in that position through the 2012 season. O’Neil spent the 2013 season as the linebackers coach for the Buffalo Bills. After the 2013 season, O'Neil was hired as the defensive coordinator of the Cleveland Browns in 2014, but was relieved of his duties after the 2015 season due to a coaching overhaul after head coach Mike Pettine was fired. He was hired by Chip Kelly on January 26, 2016 to become the defensive coordinator of the San Francisco 49ers.
NFL head coaches under whom O'Neil has served:Rex Ryan, New York Jets (2009–2012)
Doug Marrone, Buffalo Bills (2013)
Mike Pettine, Cleveland Browns (2014–2015)
Chip Kelly, San Francisco 49ers (2016)
Jim O'Neil (American football) Wikipedia