Fox was widely seen as a strong candidate to replace the fired Marc Trestman once he left the Broncos on Monday, given his record and his ties to consultant Ernie Accorsi and new general manager Ryan Pace.
Fox was the defensive coordinator for the New York Giants from 1997 to 2001 when Accorsi was the GM. Saints coach Sean Payton was the offensive coordinator for part of that time, and he is tight with Pace, who was hired out of New Orleans' front office.
Fox won the AFC West all four of his years in Denver, but each of those seasons ended in ugly losses, including a 24-13 upset by Indianapolis this year. He was 49-22 with the Broncos, including the playoffs, following a 78-74 record in nine years with Carolina, counting the postseason.
He led the Panthers to a Super Bowl with Jake Delhomme at quarterback and got back there last year with Peyton Manning. The Broncos got blown out 43-8 by Seattle, convincing general manager John Elway to spend $60 million in guarantees on new defensive players so his quarterback shouldn't have to carry the load by himself.
Fox, who in the past was criticized for being too conservative, drew more scrutiny midway through this season when the Broncos altered their offense and started to focus more on the run.
The Bears decided a shakeup was necessary after going 5-11 and missing the playoffs for the seventh time in eight years. They fired general manager Phil Emery and Trestman, the first steps in what they hope will be a drastic turnaround.
With Pace and Fox in place, the Bears can turn their attention toward filling the front office and coaching staffs and addressing a long list of roster issues.
The Bears must decide if they're going to stick with quarterback Jay Cutler after the offense took a big step backward and do something about a defense that has ranked among the league's worst the past two years.
Chicago has been to the playoffs just four times since the start of the 1995 season and only once since the 2006 team's Super Bowl run. The Bears thought they had a contender with a high-scoring offense returning intact and a rebuilt defense to go with it. What happened instead was a season-long soap opera that ended with the general manager and coach getting fired.
There was one distraction after another, whether it was linebacker Lance Briggs being allowed to miss practice to open a restaurant in California the week of the opener, former offensive coordinator Aaron Kromer admitting he was the NFL Network's source behind a critical report of Cutler late in the season or Cutler getting benched in favor Jimmy Clausen late in the season.
Cutler, who signed a $126 million, seven-year contract at the end of last season, tied Philip Rivers for the league lead with 18 interceptions. That deal makes him difficult if not impossible to trade. Cutting him is a possibility.
Another issue is the future of Brandon Marshall. He was slowed by injuries and played in just 13 games after signing a three-year extension through 2017 last May and too often drew attention for reasons that had nothing to do with performance.
Marshall, who is open about his struggles with borderline personality disorder, at one point gave a rambling news conference over past allegations of domestic abuse. He also challenged a Detroit fan to a charity boxing match on Twitter and was allowed to fly to New York on a weekly basis to record Showtime's "Inside the NFL."
Besides all that, the Bears joined the 1923 Rochester Jeffersons as the only teams to give up 50 or more points in back-to-back games in losses to New England and Green Bay. Defensive end Lamarr Houston also suffered a season-ending knee injury celebrating a meaningless sack against the Patriots.
The problems did not end there. The defense ranked among the league's worst the past two years under coordinator Mel Tucker, and a makeover that delivered Jared Allen among others did not pay off.