Simmons played junior for the the Galt Black Hawks (1948-49) and the St. Catharines TeePees (1950-51). He then turned pro with the Springfield Indians for 4 seasons and the Johnstown Jets for one. In 1956-57 he got his chance with the Boston Bruins, replacing Terry Sawchuk as the regular goaltender. He would play in tandem with veteran Harry Lumley for 3 seasons. He would tend the Boston goal from Feb. 1957 to Nov. 1960, playing in the Stanley Cup finals in 1957 and 1958.