Four Things Buffalo Bills Fans Need to Know About Jim Leonhard

Jim Leonhard is a prime candidate to become the new Buffalo Bills defensive coordinator, and here’s what fans need to know.

Wisconsin Badgers head coach Jim Leonhard prior to the game against the Minnesota Golden Gophers. | Jeff Hanisch-Imagn Images

On Tuesday, the Buffalo Bills announced their new head coach after deciding to promote offensive coordinator Joe Brady.

It seemed like a strong possibility from the moment they fired Sean McDermott that Brady would be his successor. Keeping him meant Buffalo wouldn’t have to completely reinvent the wheel, and kept other teams from poaching Brady.

MORE: 3 Free Agent WRs Bills Must Target to Help New Head Coach Joe Brady Succeed

With Brady in place, the Bills can now look to fill out the rest of the staff, which could include replacing defensive coordinator Bobby Babich. According to Adam Schefter, the leading candidate to replace Babich would be Denver Broncos assistant head coach and passing game coordinator Jim Leonhard.

Sources: Broncos defensive pass coordinator Jim Leonhard is expected to be a leading candidate to become the next defensive coordinator for the Buffalo Bills. pic.twitter.com/LuWD0G4u3a

— Adam Schefter (@AdamSchefter) January 27, 2026

Leonhard has been one of the hottest names during this coaching cycle, being linked to multiple defensive coordinator positions. If he is indeed hired by the Bills, here are four things fans need to know.

Jim Leonhard had two stints in Buffalo

Buffalo Bills defensive back Jim Leonhard against the Carolina Panthers. | Timothy T. Ludwig-Imagn Images

Leonhard played 10 years in the NFL, beginning his career as an undrafted free agent with the Bills. He played for multiple franchises following his first stint in Buffalo, then returned in 2013.

MORE:Will Bobby Babich stay with Buffalo Bills after Joe Brady hire?

That year, he had 41 tackles, six pass defenses, and four interceptions. In four seasons with the Bills, he recorded 118 tackles, nine pass defenses, and six interceptions. He was also a special teams ace, who spent time returning kicks.

Jim Leonhard has coaching clinics available online

Wisconsin Badgers defensive coordinator Jim Leonhard against the Oklahoma State Cowboys. | Mark J. Rebilas-Imagn Images

Leonhard has been a big proponent of teaching the game. During his time as a defensive coordinator at Wisconsin, Leonhard would hold coaching clinics where discussed the importance of flexibility and adapting to personnel.

He believes “football is a simple game made complicated by coaches.” Leonhard’s ability to simplify the game can be seen on YouTube where many of his clinics are available.

Jim Leonhard has been an interim head coach

Wisconsin Badgers interim head coach Jim Leonhard reacts to a play during the fourth quarter against Nebraska. | Dylan Widger-Imagn Images

During the 2022 season, the Wisconsin Badgers fired head coach Paul Chryst and named Leonhard, who was the defensive coordinator at the time, as the interim head coach. He led them to a record of 4-3, but was not retained the following season.

MORE: Josh Allen, Bills choose one former offensive coordinator over another with Joe Brady

Leonhard spent one year with Illinois, before joining Sean Payton and Vance Joseph with Denver in 2024.

Jim Leonhard runs a hybrid 3-4

Wisconsin head coach Jim Leonhard is shown during the first quarter of their game against Purdue. | Mark Hoffman/Milwaukee Journal Sentinel / USA TODAY NETWORK

When it comes to defensive scheme, Leonhard typically runs a 3-4 defense. He does, however, consider his defense a hybrid 3-4.

That means he often adapts to a four-man front based off the personnel he has. Leonhard has said this is a necessity when coaching at the collegiate level since players leave often. In the NFL, it can be just as beneficial to have a coach who isn’t rigid with their defense.

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