Khan fired Smith, the architect of the roster since 2009, and charged Caldwell with turning around one of the league's worst franchises. Caldwell's first move was ousting Mularkey, saying the team "needed a fresh start."
Many believed Caldwell would target close friend and college roommate Greg Roman, San Francisco's offensive coordinator.
Instead, Caldwell and Bradley will team up in hope of getting the Jaguars back to the playoffs for the first time since 2007. Jacksonville has missed the postseason 11 times in the last 13 years.
"The relationship between the general manager and the coach is vital," Khan said last week. "It has to be a symbiotic relationship and they have to grow together and the coach has to be somebody that it's very, very important to win and very, very important for Jacksonville."
Building the 2013 Jaguars
Bradley inherits a team that lacks playmakers on both sides of the ball.
The Jaguars have running back Maurice Jones-Drew under contract for another year and have young and talented receivers Justin Blackmon and Cecil Shorts III. But the offensive line was a mess in 2012, adding to the team's quarterback woes.
Neither Blaine Gabbert nor Chad Henne proved to be the answer.
Caldwell said he had "others in mind" to compete for the starting job.
Defensively, the Jaguars could lose linebacker Daryl Smith, defensive tackle Terrance Knighton and cornerbacks Derek Cox and Rashean Mathis to free agency. The more pressing issue will be how to generate more consistent pass rush.
The Jaguars had a league-low 20 sacks this season. Philadelphia Eagles cast-off Jason Babin helped down the stretch, but the Jaguars are likely to use the No. 2 pick in April's NFL draft to find a pass rusher.
Bradley helped develop defensive end Bruce Irvin this season. Irvin, the 15th overall pick, led all rookies with eight sacks. His defense had other young stars, too.
Linebacker Bobby Wagner, a second-round draft pick, ranked second among rookies in tackles with 140 and fourth with three interceptions. Safety Earl Thomas was voted to his second consecutive Pro Bowl, second-year cornerback Richard Sherman led the team with eight interceptions and defensive end Chris Clemons had a career-high 11½ sacks.