Bergman joined the Detroit Red Wings for the 1964–65 season and looked very comfortable as a freshman. In 58 games, Bergman held back his offensive instincts while focusing on his defensive work. Gradually he gained confidence and seniority on the team. He played solidly when the Wings reached the 1966Stanley Cup finals and lost to the Montreal Canadiens in six games. Bergman was the mantangled up with Montreal’s Henri Richard when Richard scored the Stanley Cup-winning goal against Detroit in overtime during Game 6 of the 1965–66 final series. Bergman, like all Wings from that season, was convinced Richard pushed the puck in with his glove and the goal should not have counted. He said this after the game,
"I took him down and held his stick in my hand, there was no way he could score."
Bergman continued to improve his defensive and offensive roles on the team throughout the early 1970s. His well-rounded play made him useful on both the power-play and penalty-killing units for the Wings. Although he incurred his share of penalties, Bergman wasn't considered a surly opponent on the ice. He rarely looked for trouble but also never backed down from an onrushing opponent, whether he was a fancy scorer or a power forward. While all eyes were on young superstars like Bobby Orr and Brad Park, the Red Wings were a mediocre team that continued to lose respect in the league, especially with the retirement of Gordie Howe. Bergman started turning to the community, becoming involved in many outside charities and organizations. He was particularly involved with helping disabled children and adults. He was one of the most liked NHLers off the ice due to his charity work and in 1973 he was named co-winner of the Charlie Conacher Humanitarian Award. After 10 years as a Wing, Bergman was traded to the Minnesota North Stars for fellow veteran blueliner Ted Harris on November 7, 1973. One thought as to why he was traded stemmed from Bergman speaking out when he disagreed with the decisions of coach Ned Harkness. He would post 26 points to go along with his consistent defensive play in the 1973–74 season for the North Stars. After one year he was reacquired in the off-season on October 1, 1974 by the Red Wings for Detroit's third round draft pick in 1975. He would score 30 points for his former team before being traded again the following year. Along with Bill McKenzie, Bergman was traded on August 22, 1975 for Peter McDuffe and Glen Burdon to the newly formed Kansas City Scouts where he would spend his final NHL season. In 1975–76, Bergman would record his second highest point total of his NHL career, scoring five goals and tacking on 33 assists to finish with 38 total points. Bergman retired with 367 points in 838 regular season games. In nearly a decade and a half of NHL service, he had the chance to play in only 21 post-season games, 12 of them taking place in 1966.
1972 Summit Series
In 1972 Bergman received a huge compliment when Harry Sinden and John Ferguson invited him to play with Team Canada in the 1972 Summit Series. Bergman recounted the day he was asked to play for his country,
"Harry called me Sunday morning. Janie and the kids and I were just going out the door to church, and I had to stop. Janie was saying, 'Would you get off the damn phone, we have to get to church.' It was Harry Sinden on the phone asking me if I'd be part of the team."
Bergman played an important defensive role in all eight games against the Soviets and chipped in with three assists. He would posthumously be honored for his defensive efforts in 2005, when the team was honored, en masse, as members of the Canadian Sports Hall of Fame.
