After a junior career with the Soo Greyhounds of the Ontario Hockey Association that saw him score 99 points in his only season, Simmer was selected in the third round of the 1974 NHL amateur draft, 39th overall, by the California Golden Seals. He split his first three professional seasons between the Seals and the Salt Lake Golden Eagles of the CHL, having success in the minors but receiving limited playing time in the NHL. The Seals relocated to Cleveland in 1976, but Simmer received little more playing time. He was traded in 1977 to the Los Angeles Kings, but spent the season with the Springfield Indians of the AHL, winning All-Star accolades. The next season Simmer was promoted halfway through the campaign to the Kings, and scored 21 goals in 39 games. While with the Kings, he played left wing on the "Triple Crown Line" with Marcel Dionne and Dave Taylor, one of the most potent and famed forward lines of the era. Despite injuries costing him significant playing time, Simmer had back-to-back 56-goal seasons and was further named an NHL First Team All-Star in 1980 and 1981. In the latter season, Simmer almost accomplished one of hockey's most difficult feats: scoring 50 goals in 50 games. Simmer entered his 50th game with 46 goals and scored three times to finish just shy of the mark; that same night, Mike Bossy became only the second player in NHL history to score 50 in 50. Simmer scored his 50th goal the following night in his 51st game. Simmer's shooting percentage of 32.75 in 1981 was, and remains, an NHL record. of the St. Louis Blues and Bruins teammate Mike Milbury at the Boston Garden on March 21, 1985. Simmer was traded at the beginning of the 1985 season to the Boston Bruins, where despite the cumulative effects of several injuries throughout his career, he starred for three more seasons. In 1986, Simmer won the Bill Masterton Trophy for his perseverance and dedication to hockey. Simmer played his final NHL season for the Pittsburgh Penguins in 1988. He subsequently played the 1989 season for Eintracht Frankfurt in the German Bundesliga, and after a season off, parts of two seasons as a player-coach for the minor leagueSan Diego Gulls before retiring.
