Raised in Regina, "Army" played junior in that city before making his way to the Toronto Maple Leafs for the 1937-38 season. Two years later he was involved in one of the biggest trades of the decade. He, Busher Jackson, Buzz Boll, and Doc Romnes were sent to the New York Americans for scoring sensation Sweeney Schriner.
Armstrong had three productive years on Broadway and then joined the Canadian forces. While stationed in Regina, he played for and coached the Regina Army Caps, one of the finest teams of its kind ever assembled. The top line featured himself with Don Metz and Red Tilson. He was then signed by Jack Adams in Detroit but midway through his third season in Motown he was demoted when Jack Adams called up an 18-year old named Gordon Howe.
In 1946-47 Armstrong wound up on a team called the Dallas Texans. He was the coach and star player, leading the team to the championship and being named league MVP.