"Nathaniel Hackett is a dynamic leader and coach whose intelligence, innovation and charisma impressed us from the very start of this process," Broncos general manager George Paton said in a statement. "In addition to having a brilliant offensive mind, Nathaniel is an outstanding teacher and communicator with a strong vision for all three phases of our team."
Hackett, who has worked with quarterbacks at all phases on the developmental curve, was scheduled to interview with the Jaguars on Thursday, but the Broncos stepped in Wednesday night to get a deal done to prevent him from going to Jacksonville, sources told ESPN's Adam Schefter.
It marks Hackett's first stint as a head coach, and he becomes Denver's fourth different coach since the start of the 2016 season. He replaces Vic Fangio, who was fired earlier this month after going 7-10 this past season, the Broncos' fifth consecutive losing season.
Hackett's hiring will bring immediate speculation about the Broncos trying to lure Aaron Rodgers to Denver, perhaps along with Packers star receiver Davante Adams, who is set to hit free agency in March.
Rodgers, who turned 38 last month in the midst of what could be his fourth MVP season, is contemplating his future, including retirement, after the Packers' early exit from the playoffs last weekend, when the top seed was upset at home 13-10 by the San Francisco 49ers.
Hackett, 42, emerged as the front-runner on his own merits, however, including his stellar work with quarterback Blake Bortles as Jacksonville's offensive coordinator from 2016 to 2018 before he went to Green Bay and helped Matt LaFleur win a record 39 games in his first three seasons as head coach.
Of all the offensive assistants interviewed by the Broncos, Hackett had the deepest résumé as a former playcaller for both Buffalo and Jacksonville before his time with the Packers.
During interviews with Denver, he was asked to detail how he would transition to running an entire team and how he'd construct a defensive staff. Hackett also had to answer how he would keep his game day organized if, as a first-time head coach, he were to continue to call plays.
The Broncos feature a young roster with about $50 million worth of salary-cap space projected, according to Paton, and 11 picks already in hand for April's NFL draft.
Hackett was the Jaguars' quarterbacks coach from 2015 to 2016 and offensive coordinator from 2016 to 2018 before getting fired in the middle of the 2018 season. The Jaguars reached the AFC Championship Game in the 2017 season.
When his father, Paul, was on Marty Schottenheimer's Kansas City Chiefs staff, Hackett was a ball boy for the team and even filled in as a long-snapper during drills at times. Rodgers has lauded Hackett's preparation and ability to break down and deliver information to players.
Since Mike Shanahan was hired in 1995, the only Broncos head coaches to take the team to the playoffs had previously been head coaches: Shanahan, John Fox and Gary Kubiak. None of the three first-time head coaches during that span (Josh McDaniels, Vance Joseph and Fangio) made it past three seasons.
The Broncos' defense finished among the league's top 10 in most major categories this season, and quarterback Teddy Bridgewater threw for a career-best 18 touchdowns despite missing the final three games with a concussion.
But Denver's consistently balky offense and inconsistent special-teams play ultimately cost Fangio, who went 19-30 in three years on the job.
Bridgewater was the 10th quarterback to start at least one game for the Broncos since Week 13 of the 2016 season, a total that doesn't include running back Phillip Lindsay opening behind center in a 2020 game vs. the Saints.
The Broncos are also on the lookout for a new owner.
Joe Ellis, the team's outgoing president and CEO, said that once a new head coach was in place he would release details about the franchise's future in what's expected to be the most expensive team sale in U.S. sports history.
The Broncos are valued at nearly $4 billion. If the franchise sells for that much, it would surpass the record $3.35 billion that Alibaba co-founder Joe Tsai paid for the NBA's Brooklyn Nets and the Barclays Center in 2019.
The Broncos this month cleared the final legal hurdle to a sale when a district judge ruled a right of first refusal claim stemming from late owner Pat Bowlen's purchase of the team from Edgar Kaiser in the 1980s was no longer valid.
John Elway, who is in his final months as the team's president of football operations, and Peyton Manning are expected to get involved in the bidding as minority partners of billionaires competing to win the NFL's approval to acquire the iconic franchise.
The Broncos won two Super Bowl titles in the late 1990s with Elway under center and another in 2016 with Elway in the front office and Manning at quarterback in the final game of his Hall of Fame career.
ESPN's Jeff Legwold and The Associated Press contributed to this report.