Bourque burst onto the NHL scene in 1979 after being drafted in the first round, 8th overall, by the Boston Bruins. Bourque immediately asserted himself as one of the best defensemen in the league, and won both the Calder Trophy as Rookie of the Year and a First Team All-Star selection, the first time in NHL history a non-goaltender had ever achieved such a distinction.

Bourque's prowess led him to become one of the most honored players in NHL history. During his career he was selected to thirteen First Team (the most in history) and six Second Team All-Star squads, second in total in league history only to Gordie Howe and most amongst defensemen. He also served as Boston's team captain for fourteen seasons, the longest tenure in Bruins' history and the second longest in NHL history. He won the Norris Trophy as the top defenseman in the league five times, third all-time only to Doug Harvey and Bobby Orr.

Early in 2000, Bourque requested a trade from the fading Bruins snd was traded to Colorado. Bourque proved to be a force both on the ice and in the locker room, leading Colorado defensemen in scoring, and being named an alternate captain and making the First All-Star team in his final season. Finally, on June 9, 2001, after 22 seasons, the Avalanche and Bourque won the Stanley Cup, in what proved to be Bourque's final game as a player. 

He retired with 410 goals and 1169 assists for 1579 points, all records for a defenseman. His uniform number #77 has been retired by both the Bruins and the Avalanche.