He retired from playing after the 2000 Scottish Cup Final defeat by Rangers. In that game he was substituted after three minutes, suffering a broken jaw in a challenge from Rod Wallace (requiring the insertion of metal plates into his face). With no substitute goalkeeper available, forward Robbie Winters took over in goal and Aberdeen lost 4–0. Leighton's final league appearance that season meant that he set the record for the oldest player in the Scottish Premier League at 41 years and 302 days (since broken by Andy Millen in 2007).