Jim Leonhard: The Undrafted Safety Who Became the Bills’ Defensive Coordinator
Tony, Wisconsin to Camp Randall – No Scholarship, No Problem
Don and Debbie Leonhard coached everything in Tony, Wisconsin. Football, basketball, baseball, volleyball – if a sport happened in that town, one of Jim Leonhard’s parents was probably running the practice. Several aunts and uncles coached too. So when Jim arrived at the University of Wisconsin in 2001 with no Division I scholarship offer to his name, he wasn’t exactly walking in blind. He understood football at a level most recruits don’t. He just hadn’t convinced anyone outside his county that it mattered.
Flambeau High School, enrollment somewhere south of 400, wasn’t exactly a recruiting hotbed. Leonhard played quarterback and strong safety, led the Falcons to a Division VI state championship in 1997, made first-team All-State twice. No Division I program called. He had offers to play baseball and football at smaller schools. He picked Wisconsin as a walk-on instead, gave himself one year to see if he could contribute, and set his first benchmark at something almost embarrassingly modest: get on the bus for road games.
He got on the bus.
21 Interceptions and Still Nobody Drafted Him
His sophomore season in 2002 is the one that still doesn’t fully make sense. Leonhard intercepted 11 passes, led the country, and tied the Big Ten’s single-season record. He also had 25 pass breakups and 98 tackles that year, which is an absurd combination for any safety, let alone a 19-year-old who was supposed to be earning a scholarship. Wisconsin named him team MVP – the first sophomore to get that honor since 1947.
By the time he left Madison after the 2004 season, he’d made three First-Team All-American teams, three First-Team All-Big Ten teams, and accumulated 21 career interceptions, tying the program record. He also held the Big Ten’s career punt return yardage record at 1,347 yards, a mark that stood until Michigan’s Steve Breaston broke it in 2006. The National Football Foundation put him in their 2004 college honors program. Wisconsin inducted him into their Athletic Hall of Fame in 2015.
Then the 2005 NFL Draft happened. Nobody picked him. Not in round one, not in round seven. Scouts looked at a 5-foot-8, 188-pound safety with elite production and decided the production was misleading. The Buffalo Bills signed him as an undrafted free agent and, by September, he was the only undrafted rookie on their 53-man opening day roster.
That detail gets glossed over. It shouldn’t. Making a 53-man roster as an undrafted rookie is genuinely difficult – most undrafted signings don’t survive the preseason. Leonhard not only survived, he started over time and spent four seasons in Buffalo across two stints.
Ten NFL Seasons, Six Teams, Two Torn Ligaments
The Baltimore Ravens signed him in 2008, and that’s where his career actually took off. Starting 13 of 16 regular season games while Dawan Landry was injured, Leonhard finished with 68 tackles, one interception returned for a touchdown against Cincinnati, and one sack. Those were career highs at the time, and they were good enough that Rex Ryan – then Baltimore’s defensive coordinator – wanted him when Ryan took the Jets job in 2009.
New York paid $6 million over three years, $1 million guaranteed. Leonhard started all 16 games in 2009: 66 tackles, 2.5 sacks, one interception, six passes defensed. The Jets went to the AFC Championship. Then 2010: fractured tibia in practice on December 3rd, surgery that same night, done for the year. 2011: 48 tackles in 13 games, and then during a December game against Kansas City, he intercepted a Tyler Palko pass, landed awkwardly, and tore his right patellar tendon. Carried off the field. Done again.
Two major leg injuries in back-to-back years, and he still played through 2014. Denver in 2012, New Orleans briefly in 2013 (released before the season), back to Buffalo for a personal-best four interceptions in 2013, then Cleveland in 2014 before retiring. Across 142 games and 73 starts: 431 tackles, 14 interceptions, 4.5 sacks, five fumble recoveries. Nothing that puts him in a Hall of Fame conversation, but a career built entirely on outperforming what every scout predicted.
One Year of Coaching Experience, Then Defensive Coordinator
Leonhard retired after the 2014 season, took a year off, and joined Paul Chryst’s Wisconsin staff in 2016 as defensive backs coach. No prior coaching experience at any level. He was 33 years old and, by the following February, Wisconsin promoted him to defensive coordinator after exactly one season on a coaching staff.
That’s not normal. Most defensive coordinators spend years as position coaches, then graduate to coordinator. Leonhard skipped most of that. What Wisconsin saw in that one season was something harder to teach than scheme knowledge – his players understood what he was asking them to do, and why, faster than players usually do. The 2016 Badgers finished second nationally in interceptions with 22. The secondary he coached was, by most measures, the best in the Big Ten that year.
So he took over the defense in 2017 at 34, the youngest defensive coordinator in the Big Ten at the time. Over the next six seasons, Wisconsin ranked first among all Power Five programs in first downs allowed per game (15.4), first downs allowed on third down (30.8% conversion rate allowed), and yards allowed per game (288.0). They held opponents to 17.9 points per game, fifth nationally during that span. Four times they finished in the top five nationally in total defense. Third in takeaways over those six seasons, third in interceptions.
There’s a wrinkle here that doesn’t fully add up, though: Wisconsin’s defensive recruiting was consistently below Ohio State and Michigan, yet the production was consistently above them. Leonhard was doing something with less talented players that more experienced coordinators with better rosters weren’t. The simplest explanation – that he could teach complex concepts quickly – is probably right, but it’s still worth acknowledging that those numbers were built on players who, by recruiting star ratings, shouldn’t have produced them.
Seven Weeks as Head Coach
On October 2, 2022, Wisconsin fired Paul Chryst after a 2-3 start. Athletic director Chris McIntosh handed the program to Leonhard for the rest of the season. Leonhard went 4-3, beat Northwestern, Purdue, Maryland, and Nebraska, kept the team bowl-eligible at 6-6. Then the school hired Luke Fickell on November 27, and Leonhard – who had become the clear fan choice for the permanent job – went back to coordinating the defense for Wisconsin’s Guaranteed Rate Bowl against Oklahoma State.
He coached that bowl game. Won it. Then left for Denver.
Patrick Surtain II and 68 Sacks
Sean Payton hired him ahead of the 2024 season as defensive backs coach and defensive pass game coordinator – his first NFL coaching job. In Leonhard’s first year, the Broncos ranked in the top 10 in yards allowed per pass attempt. Cornerback Patrick Surtain II won the AP Defensive Player of the Year award. Leonhard was promoted to assistant head coach heading into 2025.
The 2025 Broncos defense: 68 sacks, the most in the NFL that season, four short of the 1984 Bears’ record. Second-fewest yards allowed per game at 278.2. Third in points allowed per game at 18.3. Third in EPA allowed per pass attempt. The Broncos earned the AFC’s top seed.
68 sacks is the number that travels, but the more telling figure is yards allowed per pass attempt – Denver ranked third in the league across Leonhard’s two seasons combined. Pass defense efficiency is harder to fake than raw sack totals. It means the coverage was consistently holding long enough for the rush to work, which is a coordination problem as much as a personnel problem. Leonhard’s fingerprints were on both.
Multiple teams noticed. He interviewed with the Los Angeles Chargers and Baltimore Ravens for defensive coordinator openings before the Bills called.
Back to Buffalo – But the Run Defense Needs Work
The Bills announced the hire on January 31, 2026. Jim Leonhard, defensive coordinator, returning to the franchise where his NFL career started two decades earlier. New head coach Joe Brady called him “super intelligent, a great communicator, and highly regarded in this league” – which is exactly the kind of thing coaches say at announcements, but in Leonhard’s case there’s no obvious contradiction with his record.
What Brady actually hired him to fix is a defense that allowed the 12th-fewest points per game in 2025 (21.5) but ranked 28th against the run, giving up 136.2 yards per game on the ground. Buffalo’s pass defense was functional. Their run defense was a genuine problem. Leonhard’s defenses – at Wisconsin and in Denver – have been built around coverage and pass-rush efficiency. The run defense question is real, and nothing in his track record specifically answers it.
He replaces Bobby Babich, who coordinated the defense under Sean McDermott. The rest of Brady’s coordinator staff: Pete Carmichael Jr. at offensive coordinator (also poached from Payton’s Broncos staff), Jeff Rodgers handling special teams. The two Broncos coaches on Brady’s staff is an interesting pattern – Payton’s system clearly influenced what Brady wants to build, and Leonhard and Carmichael both know it from the inside.
Leonhard’s first season as the defensive play-caller in the NFL will come in 2026. He coordinated at Wisconsin for six years and helped run a historically productive defense in Denver for two, but calling plays on Sunday is a different job. Wisconsin opponents had a week to prepare for him. NFL offensive coordinators will have that and a full analytics department. Whether his schemes hold up against that level of preparation is the one genuinely open question – not whether he’s smart, not whether he can develop players, but whether the gap between assistant and coordinator translates cleanly to the league level. The Broncos job in 2024 was his first NFL coaching role. This is his second. That’s a fast rise by any reading of his timeline, though the results at each stop have made it hard to argue with.
What His Defenses Actually Look Like
Brady described the defensive style he wanted as “chaotic.” That word matches what Leonhard built in Denver. The Broncos pressured quarterbacks from multiple fronts, used Surtain’s press coverage to take away half the field, and forced offenses into early downs by stopping third-down conversions. Denver ranked in the top four in third-down defense allowed both seasons Leonhard was on staff.
At Wisconsin, the signature was limiting first downs – that first-among-Power-Five ranking in first downs allowed per game is really a proxy for stopping drives before they get started. His defenses don’t tend to give up easy completions underneath. The coverage stays disciplined longer than most, which is what creates the conditions for the pass rush to matter.
Buffalo’s roster gives him Siran Neal, Taylor Rapp, and a defensive line that was better at rushing the passer than stopping the run in 2025. If Leonhard runs anything close to what he ran in Denver, the Bills will blitz from multiple positions, ask cornerbacks to play press coverage on the outside, and try to manufacture a pass rush off the back of coverage that holds. The run defense concern doesn’t disappear from that blueprint, which is why the 2026 season is less a coronation than a test.
The Person Behind the Résumé
He’s married to Katie. They have three sons – Reese, Graham, and Pierce – and Leonhard grew up in a house where coaching was the family business. Rex Ryan apparently told him at some point that football is a game meant for kids, and that the coaches who forget that usually ruin it. Leonhard has repeated some version of that idea in multiple interviews: you can work extremely hard and still enjoy it. The two aren’t in conflict.
His Wisconsin players consistently described him as someone who made complexity feel manageable. The ESPN profile of him from 2017 – when he was 34 and in his first year as a coordinator – quoted people close to the program saying the same thing: he had a way of taking dense defensive concepts and distilling them into something a 19-year-old could execute without hesitating. That speed of processing, that ability to play fast because you understand exactly what you’re supposed to do, was the throughline from his playing days in Madison through every defense he’s run since.
He was inducted into the Wisconsin Athletic Hall of Fame in 2015, one year after retiring as a player. The school inducted him before he’d coached a single game. That’s a different kind of recognition than any coordinator award – it says the program considered him essential to its identity before he’d done anything in a headset.
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