Jim O'Neil enters his second season with the Lions after adding safeties to his defensive assistant title in 2025.
In 2024, O'Neil worked with one of the top safety tandems in the NFL with Lions S Kerby Joseph and Lions DB Brian Branch, who earned First-Team AP All-Pro and Pro Bowl honors respectively. Joseph became the first safety for Detroit to earn the recognition since Yale Lary in 1962 after recording an NFL-leading nine interceptions. Under O'Neil's tutelage, Branch became the only NFL player since at least 1999 to have two pass defenses in each of their first five games of a season and ended the year with the most forced incompletions (12) among safeties. With O'Neil's direction, the pair were one-of-two duos in the League to each have at least 10 pass defenses and two interceptions.
As a unit, the Lions defense allowed the lowest passer rating (82.0) and lowest passing touchdown percentage (3.0) in the League, while allowing the second-lowest completion percentage (82.0) and tied-for-second fewest passing touchdowns allowed (18) in 2024.
Prior to Detroit, O'Neil served as Northwestern's defensive coordinator for two seasons from 2021-22 and spent three seasons (2018-20) with the Raiders. He joined the organization as senior defensive assistant before being elevated to defensive backs coach for the 2019-20 seasons.
O'Neil's unit recorded nine interceptions with two returned for scores in 2019, marking the franchise's first multi-interception touchdown season since 2010. He guided S Erik Harris to career-highs in tackles (68), pass defenses (nine), interceptions (three) and defensive touchdowns (two). O'Neil also developed second-round standout CB Trayvon Mullen, whose 10 pass defenses were the most by a Raiders rookie since CB Charles Woodson had 22 in 1998.
Prior to the Raiders, O'Neil served as defensive coordinator for the San Francisco 49ers (2016) and the Cleveland Browns (2014-15).
In 2016, O'Neil oversaw a 49ers' defense that improved 13 spots to finish 14th in the NFL in passing defense, allowing just 240.5 passing yards per game. He also tutored rookie DE DeForest Buckner en route to a PFWA All-Rookie season.
During his tenure with the Browns, O'Neil directed a defense that ranked sixth in the NFL in quarterback completion percentage allowed (59.6) and tied for seventh in interceptions (32). In 2014, his unit led the NFL in lowest passer rating allowed (74.1) and completion percentage (33.3), while finishing second in interceptions (21), tied for fourth in takeaways (29) and fifth in red zone defense (46.3). Under his guidance, S Tashaun Gipson, CB Joe Haden and S Donte Whitner earned Pro Bowl honors in 2014.
Before Cleveland, O'Neil worked as the linebackers coach for the Buffalo Bills in 2013. The unit ranked second in the League with a franchise-record 57 sacks, led the League in opponent completion percentage (55.3) and tied for sixth in total takeaways (30). The Bills finished 10th in total defense (333.4 yards per game) after finishing 22nd the year prior. Under O'Neil's tutelage, LB Jerry Hughes set a career-high with 10.0 sacks.
He earned his first NFL coaching position with the New York Jets, spending four seasons with the club from 2009-12. He originally joined as a defensive quality control coach before being promoted to assistant defensive backs for three seasons.
In O'Neil's four seasons, the Jets defense combined to rank first in the NFL in opponent passer rating (71.0), completion percentage (52.6) and passing yards per game (186.3), while yielding the second-fewest yards per game (294.8). They finished in the top 10 each season in opponent passing yards per game, including a League-best mark (153.7) in 2009. In New York, he worked closely with three-time All-Pro CB Darrelle Revis and helped CB Antonio Cromartie and S LaRon Landry earn Pro Bowl honors in 2013.
Prior to entering the NFL ranks, O'Neil spent eight years coaching throughout the collegiate level. He spent the 2006-08 seasons at Eastern Michigan as a safeties coach/recruiting coordinator after stints at Towson (2005), Northwestern (2003-04), Pennsylvania (2002) and Albany (2001).
A native of Doylestown, Pa., O'Neil was a three-year starter as a defensive lineman at Towson from 1998-2000 where he received a bachelor's degree in sports management. He also holds master's degrees from SUNY-Albany and Northwestern. He and his wife, Stacy, have two sons Danny and Kellan, and a daughter, Riley.
