Born in the footballing hotbed of West Wallsend, New South Wales, Coolahan began his playing career with West Wallsend before crossing to Adamstown Rosebud in 1929. He returned to West Wallsend in 1931 though he only stayed one season before crossing to Speers Point. After another stint with West Wallsend in 1933 and 1934, he moved to Adamstown. At Adamstown he played until the end of the 1942 season. He played his final season of senior football in 1943 for Lake Macquarie.[1][2][3][4]
He played seven matches for the New South Wales state team, playing as captain once.[2] Coolahan represented Australia eight times in B international matches. He played three full international matches and was captain in all three matches. Coolahan made his full debut for Australia in Sydney against India in September 1938. He played two further games against India, the last in October 1938.[2][5]
^"Soccer Honors To Australia". Sporting Globe. No. 1696. Victoria, Australia. 1 October 1938. p. 4 (Edition1). Retrieved 24 December 2022 – via National Library of Australia.
^"William Coolahan". Football Federation Australia. Archived from the original on 30 December 2012. Retrieved 8 August 2012.
^"Hall of Fame". Hunter Academy of Sports. Archived from the original on 10 December 2012. Retrieved 8 August 2012.
India
