[2] Cain launched his National Hockey League (NHL) career with the Montreal Maroons for part of the 1933–34 season.

They were dubbed the "Green Line" and their combined offensive skills led to the teams' second Stanley Cup Championship in 1934–35.

In his one season with the Habs, or the "French" as some Boston sportswriters called them,[6] Cain stood second in goal scoring (13) behind Toe Blake (24).

[8] At the beginning of the 1939–40 season, Cain was a holdout in the Montreal Canadiens' training camp, bargaining for a better salary.

[9] Cain played his first game for the Bruins, their season opener, in Toronto on November 4, before practising with his new team.

In all ten eventual Hall of Fame forwards from Herb Cain's era, served in World War II.

On February 10, 1942, Montreal Canadiens and Boston players, archenemies during the match, hoisted the Krauts to their shoulders and skated them around the Boston Garden to honour their patriotic duty, which in large part meant being physical education instructors and playing hockey for military teams.

In 1943–44, Cain had the most productive year of his hockey career, again playing on a line with Bill Cowley and often with Art Jackson.

Occasionally Cain played on a line with right-winger Buzz Boll, who said of him, "He's so fast that he beats me to all of those loose pucks in front of the cage.

[22] In Brian McFarlane's book, The Bruins, Cain is quoted as saying that in 1946 the New York Rangers and the Chicago Black Hawks had been eager to acquire his services.

To date, Herb Cain remains the only NHL scoring champion who is not in the Hockey Hall of Fame.

Cain devoted himself to Newmarket, his wife Shirley and their children, Terry and Colleen, who claims she was skating at two.

In 1964 when Cain was diagnosed with Hodgkin's lymphoma, doctors at Toronto's Princess Margaret Hospital prescribed chemotherapy.