INDIANAPOLIS – Post-NFL life was agreeing with John Fox, until it wasn’t.

After 40 years of coaching, including 29 at the sport’s highest level, he had hit the pause button. He finally was able to enjoy so many family-related events that had been interrupted by his career.

“Got to see my kids graduate from college,’’ he said. “I was actually part of their lives, which I missed out on a lot.’’

Much of that had been left to wife, Robin. As Matthew, Mark, Cody and Halle went through the various growing stages and life events, dad was an assistant coach, a defensive coordinator and a head coach with three different NFL teams, two of which reached the Super Bowl.

But for the past four seasons, John Fox once again was knee-deep in the dad thing. He split time between the family’s home in Charlotte, N.C., and Marco Island, Fla. He got his NFL “fix” in 2018-19 as an analyst with ESPN.

“That kept me busy for two years,’’ Fox, 67, said with a laugh. “It’s a lot harder work than people realize. All the time you spend (preparing) for 30 seconds on Sports Center . . . it was mindboggling.’’

The last two years was NFL-free.

“Just kind of enjoyed life,’’ Fox said.

Then, his cell phone sprang to life.

Frank Reich was rebuilding his coaching staff – that included nearly restocking the entire defensive side in the aftermath of Matt Eberflus being named head coach of the Chicago Bears – and he reached out to Fox. He saw a deep pool of experience and defensive knowledge.

“Anyone who knows coach Fox knows that, A) he’s just a great football mind, B) great personality, great personality,’’ Reich said.

The timing was ideal for Fox. It’s not that he wasn’t enjoying life, but something was missing for someone who had been some type of coach since serving as a graduate assistant with San Diego State in 1978.

“I don’t want to say boredom because that sounds disrespectful,’’ he said. “Just being a part of something. I really missed the camaraderie, the competition, the common goal.’’

He paused.

“A purpose,’’ he said. “For me it was to really get back and be a part of that.’’

Fox carries one of those ambiguous job titles: senior defensive assistant. It’s the newest entry on his lengthy bio. His previous NFL responsibilities have been:

  • head coach with the Carolina Panthers (2002-2010), Denver Broncos (2011-14) and Chicago Bears (2015-17).
  • defensive coordinator with the New York Giants (1997-2001), Oakland/Los Angeles Raiders (1994-95) and Pittsburgh Steelers (1986-88).
  • consultant with the St. Louis Rams (1996).
  •  secondary coach with the San Diego Chargers (1992-93), Steelers (1989-91).

Taking into account prior stints with the USFL’s Los Angeles Express and various colleges, Fox had been at it nonstop as a coach since 1978.

The only “break?” He temporarily relinquished his head coaching with Denver in 2013. Fox underwent aortic value replacement surgery Nov. 3 and was back at work four weeks later.

His three-team head coaching experience spanned 16 seasons and was unique in that there was no break between any of them. That was rare but not unprecedented. Dan Reeves had a 23-year run with Denver, the New York Giants and Atlanta without any time off. And Chuck Knox’s 22-year NFL career involved four teams – the Los Angeles Rams, Buffalo, Seattle and the Rams again – with no time to decompress.

“You get burned out, and you don’t even realize it. That was a grind,’’ Fox said. “It’s been a good break. I think it’s a break I needed in hindsight.’’

Reich’s call ended the hiatus.

Now, Fox is part of coordinator Gus Bradley’s staff that also includes two of Fox’s long-time friends/former assistants. Linebackers coach Richard Smith and defensive backs coach Ron Milus were with Fox both in Carolina and Denver.

“And Gus I knew just from coming up through the profession,’’ said Fox, whose history with Reich can be traced to when both lived in Charlotte.

Fox met with Reich during his time with the Panthers, but there wasn’t an opening on his staff. So impressed with Reich, he still had him talk with the team.

“He was somebody I was really comfortable with to come and do this,’’ he said. “Not only really good coaches, but really good people.’’

While Fox’s job description might be vague, his presence should prove invaluable. During his 16 years as head coach, his defenses ranked in the top-10 seven times. He took seven teams to the playoffs and two – the ’03 Panthers and ’13 Broncos – reached the Super Bowl.

“Whenever you’ve accomplished something, you try to stay humble and keep your humility,’’ Fox said. “It’s been kind of easy. I do think I have some wisdom. I do have some experience.

“I’m not going to say it’s my way or the highway. I’ve done it so many different ways that you know there’s many ways to do it.’’

The bottom line: It’s Gus Bradley’s defense.

“My whole objective has been to come in here and learn their system, Gus’ system,’’ Fox said. “If there are any little things that I can stick in, you mention it. If they don’t like it, no big deal.’’

Thus far, Fox has been everything Reich anticipated.

“Here’s what I appreciate about the way he’s handled it,’’ he said. “He’s just there to serve. Like, ‘Hey, I’m not here to take over. What role do you want me to play? How can I assist? Do you want me to help out a little bit of emphasis on third down or red zone?’

“I think that’s working well.’’

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You can follow Mike Chappell on Twitter at @mchappell51.