PITTSBURGH – Defensive coordinator was Mike Tomlin’s dream job when first-year Vikings coach Brad Childress hired him in 2006 to command his underwhelming unit.

Tomlin was 33. He had been an NFL secondary coach for just five seasons in Tampa Bay. Nobody in the league had him on their head-coaching radar, certainly not the iconic Pittsburgh Steelers.

One year building a stout run defense with Minnesota distinguished Tomlin as the next-generation steward in Pittsburgh, where he counts a Super Bowl XLIII victory among seven playoff appearances in 11 seasons entering the Sunday, Sept. 17, game against the Vikings at Heinz Field.

Childress’ ringing endorsement and superior interviews with Steelers executives in January 2007 rocketed Tomlin over the leading candidates at the time, including internal favorites Russ Grimm and Ken Whisenhunt and that offseason’s trendy defensive coordinator, Ron Rivera.

“I probably would have told you then Mike was not the guy we were going to hire,” Steelers owner Art Rooney II recalled Thursday.

“He was on our list but only one year as a coordinator was the scary part, there’s no denying it. But every time we talked to Mike we felt better and better about him. He has that presence in a room that you look for; that you know will keep the players’ attention day in and day out.”

Day in and day out over the past decade, Tomlin has built the Steelers into an AFC North powerhouse, stalking the sidelines in aviator sunglasses on a foundation of aggressive defense and an equally tough Ben Roethlisberger, the future hall of fame quarterback he inherited.

Tomlin’s 104-57 record ranks third behind Green Bay’s Mike McCarthy (115-61-1) and New England’s Bill Belichick (237-116) among active coaches.

Tomlin has won five division titles and eight playoff games. He has never suffered a losing season in Pittsburgh. His only blemishes are consecutive 8-8 finishes in 2012-13.

Sustained success has earned Tomlin job security that is the Steelers’ legacy. The franchise has had only three head coaches since 1969.

The championship through-line of Chuck Noll and Bill Cowher to Tomlin is a remarkable run of sideline stability in a win-now league defined by short coaching leashes and rapid turnover.

“I don’t take it for granted,” Tomlin said. “We’ve got stability because we consistently win. So I’m aware and cognizant of that.”

Before Tomlin won over the skeptical Steelers brass, he had to prove his worth to Childress, whose aggressive courtship commandeered Vikings owner Zygi Wilf’s private jet to shuttle him to Minnesota for interviews.

Wilf wanted an innovative coordinator to manage the defense while Childress, Philadelphia’s former offensive coordinator, focused on his side of the ball.

Tomlin was a disciple of Tony Dungy’s “Tampa-2” defense with the Buccaneers, the fashionable pass coverage scheme Childress wanted to use. Two days after Tampa Bay’s wild-card playoff loss to Washington, Tomlin and his wife were on their way to Winter Park for contract negotiations.

“I knew he’d be hot property and was at the end of his contract so we wanted to go get him,” recounted Childress, now an assistant head coach with the Kansas City Chiefs. “The list was all but one guy — Mike. Zygi was good enough to let us use his jet, and we quickly did the deal.”

In Minnesota, Tomlin earned the respect of an established defense that included defensive linemen Kevin and Pat Williams, veteran cornerback Fred Smoot and Pro Bowl safety Darren Sharper, who played with Tomlin at William & Mary.

Childress was hardly surprised. With Tampa Bay, Tomlin won a Super Bowl coaching Pro Bowl safety John Lynch, who was a year older than his coach. And he more than held his own within a defensive group of outsized personalities like Ronde Barber, Warren Sapp and Derrick Brooks.

“Communication was key or those guys would eat you up if you didn’t know what you were doing,” Childress said.

The Vikings finished a disappointing 6-10 in 2006. However, Tomlin improved their defense from 21st in the NFL to eighth, including No. 1 against the run despite being tied for last against the pass.

His organizational skills and charisma shined through as a head-coach-in-waiting. Tomlin was passionate in player meetings. He prepared an opening statement for his weekly news conferences and answered reporters’ questions with refreshing veracity.

As the head coaching carousel started in January 2007, Tomlin was uncertain he wanted to leave Minnesota after one season and take a spin.

“It just evolved,” he said. “I had been dreaming a lot of about getting an opportunity to run a defense (and) was excited about the work we had laid down there. That was my focus, to be honest with you. The head coaching opportunity was something that just kind of developed.”

Childress already was fielding calls about his defensive coordinator from Miami and Pittsburgh, and needed to know if Tomlin was all-in about the opportunities.

“I said you can’t go into this half-baked on the idea, especially if it’s a matter of public record,” Childress said. “The next day he came back and said, ‘Yeah, I want to do it’ and the process was in place.”

Miami Dolphins owner Wayne Huizenga flew into the Twin Cities and wined and dined Tomlin on his jet. Rooney, who was Steelers president at the time, called Childress seeking permission to interview Tomlin shortly after Cowher resigned.

“I asked Art, ‘Do you want the truth or do you want me to lie?’ ” Childress said, chuckling. “He told me to give him the truth. I said you can trust him implicitly on defense, he has a great way about him and he can run any room.”

A similar recommendation by Dungy helped convince Rooney that the young coach who blew the team away in his interview at Heinz Field was the right choice.

Noll was 37 when the Steelers hired him in 1969, and he went on to win four Super Bowls. Cowher was 34 when he succeeded the legend in 1992 — the same age as Tomlin when he took over.

The Steelers’ investment in young coaches comes with a commitment to let them grow.

Noll posted losing seasons his first three years before establishing his dynasty in the 1970s. Cowher lost four AFC championship games before finally breaking through with a Super Bowl XL win.

“We certainly have managed to have good guys that won, and that’s the bottom line,” Rooney said. “We have had a year or two here and there that were down years. You have to recognize that’s going to happen and you have to be comfortable with the process your coach is going through to come back from those years.

“That’s the hardest part of the evaluation process is having the confidence you’ll have a bounce back with this coach. You’re not going to win every year in this business. You have to be prepared to live through hard times and feel confident in your man when that does happen.”

Tomlin’s hiring also was symbolic.

He was Pittsburgh’s first black head coach, hired by late owner Dan Rooney, author of the 2002 “Rooney Rule,” which requires teams to interview at least one minority candidate before selecting a head coach.