PHOENIX — Joe Cullen changed the vibe.
The veteran assistant coach landed in Kansas City in the offseason — the seventh stop in the Quincy, Mass., native’s NFL journey — and he left an immediate impression on the Chiefs defensive linemen.
The group, which featured bookend standouts Chris Jones and Frank Clark, knew things were about to change. For the better. This unit would no longer be labeled as underachievers.
“Coach Cullen came around with a big personality, a deep voice,” said Clark. “He’s been great for us. I feel like he was the missing piece that we needed on the defensive line. His personality, his demeanor, his aura. He pushed us to be great every day.”
Jones, arguably the most disruptive tackle in the league and a candidate for Defensive Player of the Year, was similarly impressed.
“Bringing him in completely changed the D-line room for us,” said Jones. “He pushed us beyond the measures.
“I can sit up here all day and tell you about the good things and how he was able to transform that room, because basically we still had the same group of guys ... but I think everyone is playing better and on a different level than we were last year, and that’s because of Joe Cullen.”
Changing the vibe isn’t something new for Joe Cullen.
Following a decorated playing career at Quincy High (Suburban League All-Star fullback and linebacker, Shriner’s Classic MVP) and UMass (three-time All-Yankee Conference nose guard), he began a college coaching odyssey that included stints at UMass, Richmond, LSU, Memphis, Indiana, and Illinois before the NFL — specifically the Detroit Lions — came calling in 2006.
His taste of life in the pros was almost short-lived, however. Before the season even started, Cullen was arrested in Detroit twice for embarrassing, alcohol-related incidents.
It would have been easy for the Lions to discard their new defensive line coach, but head coach Rod Marinelli, general manager Matt Millen, and the Ford family chose to support him.
“They stuck by me; I wouldn’t have stuck by me, but they did,” Cullen said this week as he prepared for Super Bowl LVII Sunday. “I had never really been in trouble, but basically I drank too much. So I realized my family name, where I came from, my career, it could have all been over.”
So Joe Cullen changed the vibe.
He served a one-game suspension (he still counts NFL commissioner Roger Goodell among his supporters) and he put those arrests — and alcohol — behind him.
Following three seasons in Detroit, he had trouble landing another NFL gig, so he took a job at Idaho State for a year before Jack Del Rio (”another great mentor,” said Cullen) brought him to Jacksonville.
Since then, he’s had stops in Cleveland, Tampa Bay, Baltimore, Jacksonville again, and now Kansas City.
He uses his story as a way of helping others — including his players — when they are faced with any kind of adversity.
“First of all, you’re going to get knocked down; things are going to happen,” said Cullen, 55, still proudly in possession of his Boston accent. “But if you’re really remorseful, whatever happens, and you’re honest with yourself and you really want to become better and learn from your mistakes, great things can happen, and that’s part of my journey.”
The next stop on the ride comes in Glendale, where he has a chance to win a world championship. It’s a long way from Veterans Memorial Stadium in Quincy and McGuirk Alumni Stadium in Amherst, Mass.
“It’s the pinnacle,” said Cullen. “To get to this level, the highest level, and to be in the championship game, it’s a great feeling. You know, there were some bumps along the way. But that’s part of life.”
His players aren’t the only ones heaping praise on Cullen. Andy Reid, whose father, Walter, grew up in Quincy, and defensive coordinator Steve Spagnuolo, who grew up in Grafton, Mass., marveled at the job he’s done.
“He brings a ton of energy and he’s very smart,” said Reid. “He knows the game. I think the guys play hard for him. They like being worked hard and he works them hard. That’s a unique thing to be able to do.”
Spagnuolo joked that the key to Kansas City’s defensive success might be the heavy New England accents he and Cullen carry.
“Maybe they can’t understand what we’re saying,” he said with a chuckle.
“Joe’s been terrific. I’ll tell you what, you can ask every one of those defensive linemen and they’ll tell you what impact he’s had. He’s got some juice, too. He played the position.
“I love Joe. I knew what he would give us in that room, and it’s been great to watch those guys develop with him.”
Apprised of the kind words of others, Cullen quickly deflected.
“To get to learn from Coach Reid and Coach Spagnuolo and be around guys like Chris Jones and Frank Clark,” said an emotional Cullen, shaking his head as his voice trailed off. “It’s special.”
Cullen appreciates how his players bought in and how his veterans not only worked every practice rep but also spent time mentoring the younger Chiefs.
It all starts with Jones, he said.
“For us to get where we wanted to be, we all had to have career years, and Chris had his best year,” said Cullen.
A victory over the Eagles may even supplant one of Cullen’s all-time favorite football moments.
“Beating North Quincy on Thanksgiving my senior year,” he said, recalling the game as though it were played last weekend. “They were really good, and they had two 1,000-yard rushers. Coach [Jack] Raymer put together a game plan that was one for the ages. We shut down their run game. It was a game we didn’t want to lose. We kept them out of the Super Bowl.”
Now Joe Cullen is on his way to the Super Bowl and no one is going to keep him out.
Jim McBride can be reached at james.mcbride@globe.com. Follow him @globejimmcbride.