Haynes started his National Hockey League career with the Montreal Maroons. He would also play with the Boston Bruins and Montreal Canadiens. His career lasted from 1931 to 1941. Haynes played in 390 NHL games, scoring 61 goals and 134 assists. Haynes played for the Canadiens for five more seasons and retired in 1941. He discovered future stars Elmer Lach and Ken Reardon for the Canadiens after getting injured and being sent on a scouting tour of Western Canada.