Two of Mulhall's elder brothers had forged professional careers; Martin with Falkirk, Albion Rovers and Cowdenbeath, and Edward with East Stirlingshire.
Mulhall initially had difficulty breaking into the Aberdeen first team, as his left wing position was occupied by Jackie Hather.
[5][4] Mulhall made 289 appearances and scored 67 goals for Sunderland,[3] and he helped the team to win promotion to the First Division in 1963–64.
[3] He won another two international caps, also against Northern Ireland, before moving to South Africa to play for Cape Town City in 1969.
He later returned to Halifax Town as joint manager with Kieran O'Regan and got them promoted back into the Football League in 1998,[5] at which point Mulhall retired.