Briere was selected in the third round 26th overall by the Pittsburgh Penguins in the 1969 NHL Amateur Draft and would have gone much higher but for his somewhat diminutive stature. During his final year as a junior, he scored 75 goals and 86 assists for 161 points for the Shawinigan Falls Bruins of the QMJHL. He was also selected as an add-on player for the QMJHL champion Sorel Blackhawks for the 1969 Memorial Cup series against the Montreal Junior Canadiens, who at the time were playing out of the Ontario League. Montreal, with the likes of Rejean Houle and Marc Tardif leading the way, won the series, but Briere was acknowledged as the premiere performer for the Hawks and scored two goals in their only win. The previous year, Briere scored 54 goals and 105 points in 50 games for the Bruins. In 1968 he was chosen to the QMJHL Second All-Star Team and he was a First Team selection in 1969.

The professional hockey chapter of his life began well. He made the Penguins roster as a 20-year-old rookie in 1969-70, scoring 12 goals and 44 points in 76 games. He was named the team's rookie of the year, and by all accounts, most NHL observers felt he was going to be a future star in the league for many years to come, being mentioned with other such rookie phenoms as Bobby Clarke and Tony Esposito.

However, the dream life turned into a tragic nightmare on May 15, 1970. While driving with two friends near his hometown of Malartic, making preparations for his wedding that summer, the Briere vehicle was involved in a horrific car crash, which threw him clear of the car. The other two occupants survived the crash, but suffered multiple fractures. When emergency crews arrived on the scene, they found Briere unconscious, some distance from the car. "He was in the back seat," Penguins coach Red Kelly recalled. "There wasn't even a mark on him. But he was thrown out, and there was damage to his brain." But there would be yet another tragedy associated with the crash on that fateful rainy evening. On the way to transporting the severely injured Briere to hospital in Val D'Or, the ambulance transporting him struck and killed an 18-year-old pedestrian, a young man by the name of Raymond Perreault of Malartic.

Briere lay in a coma for seven weeks before showing signs of consciousness. The owner of the Pittsburgh Penguins, Donald H. Parsons, told the Briere family that he would provide lifetime financial security for Briere, if he was unable to resume his hockey career. He remained in a twilight condition, between consciousness and unconsciousness for close to a year and underwent four operations before dying of his injuries on April 13, 1971 at the age of 21.

Coach Kelly once said a goal by Briere is one which he'd always remember. It was a game against the St. Louis Blues. "Michel was going over the blue line and he put a shift on the defenseman, who took the fake and started going to his right," Kelly recalled. "Jacques Plante went for the fake too, even though Michel just crossed the blue line and he shot the puck in the open side of the net. That's how elusive he was on the ice."

Jack Riley, the Penguins general manager at the time, has his own memories of Briere. "When we tried to sign him, he wanted more bonus money." The extra money was an additional $1,000 on top of the basic $5,000 offered as a signing bonus. "It's not really that much extra money, because I'll be playing for the Penguins for the next 20 years" Riley recalled Briere telling him.

Briere and Mario Lemieux are the only two players in Penguins' history to have their numbers retired. Although Lemieux returned to once again wear his number 66, number 21 will never again be worn by anyone with the Pittsburgh Penguins.

The QMJHL named its MVP award the Michel Briere Memorial Trophy in 1972. Coach Kelly still has still has a stick autographed by Briere at his home in Mississauga, Ontario.