Steve Casey debuted as a professional wrestler on 3 March 1936 by beating the Irish Canadian Heavyweight Champion Paul Duveen in a non-title match.

On 11 February 1938, he received the biggest victory of his career when he defeated the legendary Lou Thesz to win the Boston-based American Wrestling Association World Heavyweight Championship.

In September 1938, promoter Tom Packer switched recognition to National Wrestling Association champion Everett Marshall.

In later years the similarly initialled National Wrestling Alliance asserted that Casey had been stripped of the original NWA title for being out of the country - this would be cited as an example of enforcement of the "thirty-day rule.

On 29 March, he beat Gus Sonnenberg to start his second reign as AWA champion, losing the title to Ed Don George on 18 April in Albany, New York.

He defeated George to start his third reign as AWA World Champion on 3 November 1939 at Broadway Auditorium, dropping the title to The French Angel on 13 May 1940.