[2] After his playing days were over, Hainsworth returned to Berlin (now named Kitchener) with his wife Alma and son Bill.

At that time, Newsy Lalonde, manager of the Western Canada Hockey League (WCHL) Saskatoon Crescents, needed a goalie.

On the recommendation of Montreal Canadiens' part-owner Leo Dandurand, Lalonde signed Hainsworth to a pro contract of $2,500 per season with Saskatoon.

[5] In 1930 he set an NHL record that still stands, going 270 minutes and 8 seconds without allowing a goal during the playoffs for the Canadiens.

Hainsworth was traded to the Toronto Maple Leafs in 1933 for Lorne Chabot in a move by Dandurand to land another French-Canadian on his roster and boost attendance.

In 1936, Turk Broda won the goaltender job for Toronto, and Leaf manager Conn Smythe gave Hainsworth his outright release on November 25, 1936.

[8][9] In 1936, Hainsworth became a radio inspector with Dominion Electrohome Ltd. During World War II, he was a member of Kitchener's civil defence guard.

[10] Hainsworth died in a head-on collision between his car and a light panel truck near Gravenhurst, Ontario, on Monday, October 9, 1950.