During his second stay with the Vikings in the early '90s, some perceived him as a "behind the scenes guy" according to another staff member. And there were issues with other teams.
Schottenheimer hired him for the Browns. But the next year owner Art Modell fired Schottenheimer and promoted Trestman to offensive coordinator when he hired Schottenheimer's replacement, Bud Carson.
"We forced him to keep Trestman," said Ernie Accorsi, who was the Browns' general manager at the time. "You can't do that. In this business with the way everybody is looking around corners, he immediately was painted as management's guy. Marc was not hard to get along with, but he didn't get along with Carson under those circumstances."
In early 1990, 15 minutes after his marriage on a golf course in Hawaii, Trestman returned to his honeymoon suite to see a light flashing on his telephone. He was fired.
But his worst coaching experience came 15 years later.
Trestman had been an offensive coordinator seven of the previous eight seasons and had achieved outstanding results working with the likes of Rich Gannon and Steve Young. He went to the Dolphins at the behest of Norv Turner, then the offensive coordinator, to be assistant head coach and quarterbacks coach.
Then, as Trestman flew from Oakland to Miami, Turner was on a plane to Oakland to become the coach of the Raiders.
Trestman was by far the most qualified assistant on the Dolphins staff to replace Turner, but Wannstedt instead promoted running backs coach Joel Collier because, he said, he wanted to maintain Turner's system and remain primarily a running team. Health issues forced Collier to step down before training camp opened, and Wannstedt bypassed Trestman a second time, promoting tight ends coach Chris Foerster.
Neither Collier nor Foerster ever had coordinated offenses before. The concept was the offense was supposed to be run by committee. But the committee couldn't agree on anything, and the team imploded.
"We had some good coaches there, but I don't know if it ever got organized on who was doing what," said Vikings general manager Rick Spielman, who was the Dolphins general manager at the time. "I remember some of the thoughts and ideas he had that were great, but I don't know if they all meshed with everybody else's ideas."
Assistants with the team said Trestman challenged decisions, and some of the other offensive coaches resented him for it.
"There were a lot of issues," Wannstedt said. "Fault me, not Marc."
Said Trestman, "I thought I was going to be there with Norv. It wound up being a completely different situation. I thought Dave Wannstedt treated me extremely well. That was a learning moment for me. I think I was carrying some baggage that I would admit to from getting fired in Oakland. There was some leftover anger and disappointment. As I look back, I would take accountability that I could have done a better job there in Miami."
The whole Miami staff was swept out after the season, and Trestman would not work full-time in the NFL again until Phil Emery hired him in Chicago eight years later.
Trestman turned down a chance to be the offensive coordinator of the Saints and instead decided to make a move that he thought was better for his young family. He would leave the NFL and become offensive coordinator for North Carolina State.
It was then that Trestman started to see his job from a different perspective.
In his book "Perseverance: Life Lessons on Leadership and Teamwork," Trestman wrote, "You see, as a college coach I became a teacher, a father, a confidant, a mentor; not just a guy trying to make first downs. It was an entirely different mindset. I began to realize that for some, I was the first male figure in their lives away from home. They became my children, in a sense, and I began to care deeply about each and every one of them in a way that went beyond the game."
Trestman and his family were comfortable living in Raleigh, N.C., and he envisioned himself finally taking root in his job and community.
But then the entire staff was let go after his second season. He said it was the most devastating firing of his career. It left him "bitter, angry and crushed."