Wally Hanlon was born in Glasgow in 1919 and began his career at Clyde. In 1946, he signed for Brighton & Hove Albion where he made 72 appearances over the next two years, scoring four goals. He then spent a season with Bournemouth & Boscombe Athletic, where he made 19 appearances, scoring three times.
In July 1949, Wally signed for Crystal Palace. Between then and June 1955, he made 125 League appearances for the club, scoring nine times. He then moved into non-league football with Sudbury Town.
Wally was granted a benefit match by Crystal Palace, which took place on 30 April 1954, against a London XI.