He played three years with New York before World War II, in which he went to play and coach for the Regina Army Caps. Following his army service, Armstrong was signed by Jack Adams in Detroit, but halfway through his third season he was demoted after Adams called up an 18-year-old named Gordon Howe. In 270 career NHL games, Armstrong scored 67 goals and 121 assists for 188 points.
Before World War II, he played three years with the New York team before moving to Regina to play and coach for the Army Caps. After his military service, Armstrong was signed by Jack Adams in Detroit but was demoted after Adams called up an 18-year-old player named Gordon Howe. In 270 NHL games, Armstrong scored 67 goals and 121 assists for a total of 188 points.