Born in Halifax in 1918, Billy Hannon starred in hockey, baseball, and softball, in a career that began in the early 1930s and spanned a quarter of a century.

Hannon began his senior career with the Middleton Maple Leafs in 1936 before suiting up in 1938 with the Halifax Junior Canadians. He scored 36 goals in eight regular season games and 42 more in 15 playoff games with the Junior Canadians. Lester Patrick, of the New York Rangers, invited him to camp after taking notice of his fine play. As a result, he was selected as one of the 15 players to play for the Rangers top minor team, the New York Rovers of the EAHL. He was ninth in scoring.

After the war, he returned to the EAHL with the Baltimore Clippers where he amassed 46 goals and 40 assists in the 1946-47 season.

Hannon was a fine baseball player with the Halifax Arrows, Halifax Shipyards and the Halifax Capitals of the H&D League from 1946 to 1950. Hannon won the H&D League, Nova Scotia and Maritime championship as a member of the Arrows in 1947 and the Capitals in 1948.