Sealey joined Coventry City as an
apprentice in 1975 and made his debut as a 19-year-old on 11 April 1977, in a 1–1 draw at
Queens Park Rangers. He spent the next five seasons at the
West Midlands club before joining Luton Town in 1983 for £100,000. He was a regular in the team for much of his time at
Kenilworth Road, but he missed their 1988
League Cup triumph due to injury, his place being taken by
Andy Dibble. A year later, Luton reached the final again and he was able to keep goal this time in a 3–1 defeat to
Nottingham Forest in which Sealey had a poor game, including fouling
Steve Hodge to concede a penalty (converted by
Nigel Clough). He was dropped from the team for Luton's next game and replaced by
Alec Chamberlain. Sealey never played for Luton again. In December 1989, Sealey was loaned to Manchester United and made two league appearances during the final weeks of the season. He was named as goalkeeper for the
1990 FA Cup final replay against
Crystal Palace after a poor display from
Jim Leighton in the preceding 3–3 draw, and made several saves to help his side win 1–0. He later offered his winner's medal to Leighton, who had played throughout the cup run, but the FA subsequently granted medals to both players, who remained friends thereafter. 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. He had several games on loan at
Birmingham City during the opening weeks of the
1992–93 season before returning to Manchester United on a free transfer in January 1993, this time as
Peter Schmeichel's understudy.{{cite news In his second spell at
Old Trafford, he made just two first-team appearances – once as a substitute when Schmeichel was sent off in the FA Cup Quarter-final against Charlton and the other in the League Cup final for which Schmeichel was suspended, which United lost 3–1 to his old club, Aston Villa.{{cite news At the end of the season he was given a free transfer and joined
Blackpool, but within six months he had left
Bloomfield Road and returned to the
Premiership with boyhood heroes West Ham. Due to an injury crisis, Sealey made his Hammers debut as an outfield player, coming on as an attacking substitute against
Arsenal in a 1-0 defeat on 16 September 1995. During his 18-month spell at the
Boleyn Ground, he was understudy to
Luděk Mikloško. Sealey joined
Third Division club
Leyton Orient in 1996, and was their first-choice goalkeeper from the start of
1996–97. In December 1996, the 39-year-old Sealey returned to West Ham in an exchange deal for 47-year-old
Peter Shilton. He made his last first-team appearance on the final day of the
1996–97 season, fittingly against Manchester United at Old Trafford. He had come on as a substitute for
Luděk Mikloško, West Ham's regular first-choice goalkeeper. At the end of the
1997–98 season he was loaned out to
Bury but did not make a first-team appearance. Upon his return to West Ham he was appointed as the club's goalkeeper coach, although he was still registered as a player during the
1999–00 season, taking him past his 42nd birthday in September 1999. ==Personal life==