The midfielder spent three seasons with the Seagulls between 1981 and 1984 and captained the side in the 1983 FA Cup final against Manchester United.
Grealish also played for Leyton Orient, Luton, West Brom, Manchester City, Rotherham and Walsall, and made 45 international appearances for Republic of Ireland between 1976 and 1986.
A statement on Brighton's website read: "On behalf of everyone at the club, our thoughts go out to partner Wendy, children Garret and Jordana, grandchildren Harrison and Joshua, likewise Tony's mother Nora, brother Brian and sisters Anne and Christine at this very sad time."
- Sports & Recreation
- Leyton Orient
- West Brom