New Buffalo Bills head coach continues to add to his coaching staff, this time bringing in former Bills safety Jim Leonhard to serve as the team’s new defensive coordinator.
Leonhard, 43, previously served
as the Denver Broncos’ secondary coach and passing game coordinator and had also interviewed with the Baltimore Ravens and Los Angeles Chargers for their defensive coordinator job.
Today’s edition of Buffalo Rumblinks reintroduces Bills Mafia to Leonhard, who has never overseen an entire NFL defense, but is considered a rising defensive mind since he retired after 10 seasons, including two stints with the Bills.
Former Bill Jim Leonhard named defensive coordinator
After tabbing current Denver Broncos senior offensive assistant Pete Carmichael Jr. as their new offensive coordinator, Joe Brady and the Bills went back to Denver to find their next defensive coordinator.
Leonhard had two stints playing for the Bills, first from 2005-07 and again during the 21013 season. Leonhard served as the defensive passing game coordinator under defensive coordinator Vance Joseph in 2024, helping to orchestrate one of the league’s best boundary secondaries, including Pat Surtain II, the 2024 Defensive Player of the Year. He was promoted to assistant head coach and defensive pass-game coordinator in 2025.
Leonhard was also the defensive coordinator with the University of Wisconsin from 2017-2022, where his defenses were consistently ranked among the best in college football for efficiency, turnovers forced, and red-zone defense. He also served as interim head coach for the Badgers in 2022.
The hiring of Leonhard could represent the dawn of a new defensive era at One Bills Drive. While Buffalo employed a 4-3 defense under former head coach Sean McDermott, the defenses Leonhard ran at Wisconsin and helped run in Denver all ran a base 3-4 defense.
- Source: Buffalo Bills to hire Jim Leonhard, former safety, as defensive coordinator – Buffalo News (subscription required)
- Bills hire Broncos’ Jim Leonhard as defensive coordinator – The Athletic (subscription required)
- Jim Leonhard’s defensive stats at Wisconsin were absolutely dominant, and now he’s headed to Buffalo Bills – newyorkupstate.com
- Bills hire former player Leonhard to run defense – ESPN.com Buffalo Bills blog
- Jim Leonhard returning to Bills as DC – Democrat & Chronicle
- Bills hire former Buffalo safety Jim Leonhard as defensive coordinator – BuffaloBills.com
- Bills hire Jim Leonhard to be new defensive coordinator – WGR 550
- New Bills coach Brady fills defensive coordinator job by hiring Leonhard – WGRZ
- Bills hire Broncos assistant head coach Jim Leonhard as defensive coordinator – NFL.com
- Four Things Buffalo Bills Fans Need to Know About Jim Leonhard – Sports Illustrated Buffalo Bills
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