Hanrahan made his first grade debut for University in round 1 of the 1928 NSWRFL season against EasternSuburbs at the Royal Agricultural Society Showground. Hanrahan spent three years at University with two of them seeing the team finish in last place. He was their top try scorer in the 1929 season. In 1933, he played one season with Eastern Suburbs where the club reached the preliminary final against St. George. In 1935, Hanrahan played one year at South Sydney but did not feature in their grand finalloss to Eastern Suburbs. Hanrahan represented New South Walestwice in 1929. He also represented both NSW Country and NSW City. Hanrahan is also listed as playing for Jambaroo in the NSW Country competitions.