He was drafted 29th overall by the Pittsburgh Penguins in the 1976 NHL Amateur Draft. Thsi came after an excellent junior career with the Sherbrooke Castors of the Quebec Major Junior Hockey League. He won the most valuable player award in his final season in 1975-76. Rather than join the Penguins Marsh opted for the Cincinnati Stingers of the World Hockey Association (WHA). He played three seasons there. His NHL rights had been traded to the Montreal Canadiens as part of the Pete Mahovlich trade. When the WHA and NHL merged in 1979, Marsh ended up with the Winnipeg Jets.