United signed Sealey on a permanent basis, and he was their regular goalkeeper throughout the 1990–91 season, keeping goal in their League Cup Final defeat to Sheffield Wednesday (in which he was injured, but refused to leave the field) and the Cup Winners' Cup Final victory over Barcelona the following month. He became a cult hero with United fans and got a standing ovation whenever he returned to Old Trafford. He was hoping to get a two-year contract, but was offered just a one-year deal and turned it down in favour of a transfer, and was signed by Aston Villa. For much of the first half of 1991–92, Sealey was Villa's first-choice goalkeeper, but he then lost his place to long-serving Nigel Spink and never played for the club again.