Foster first rose to prominence as a hockey player in the Winnipeg Junior Hockey League in the early 1920s. With the Winnipeg Argonauts, and later the University of Manitoba, Foster earned a reputation as "the world's finest goaltender." His team won the Manitoba Junior Provincial Championship in 1925, and he was a two-time winner of the Manitoba Championship, first in 1927 with the Winnipeg Winnipegs and in 1930 with the Elmwood Millionaires.
In 1931, he joined the Moncton Hawks of the Maritime Senior Hockey League, a team which he led to the Allan Cup finals in 1932. Foster went an astounding 417 minutes without allowing a goal. He also led the Hawks to victories in the Allan Cup in 1933 and 1934, and during his three seasons with the team, he missed only one game.