He made more than 100 League appearances for each of his first three clubs – Portsmouth, Manchester City and Fulham. He played for Fulham until December 2001, when he was signed by Crystal Palace for £400,000, the club at which he finished his playing career after 60 senior appearances.
Symons won 36 caps for Wales, scoring twice. His first appearance was against the Republic of Ireland on 19 February 1992 and his last appearance was on 6 October 2001 against Belarus. Symons qualified to play for Wales because his father was from Cardiff.
Symons spent some of his time at Crystal Palace as a player-coach, and after retiring from playing became a full-time member of the coaching staff. He became caretaker player-manager for a short while in 2003, and following the subsequent appointment of Iain Dowie he combined the roles of player and assistant manager.
After Taylor was dismissed from the Eagles on 8 October 2007, Symons was confirmed as Caretaker Manager until the appointment of Neil Warnock three days later (Palace did not play during this time). Following Warnock's appointment, Symons stepped down from his position of Assistant Manager and left the club on 15 October.
Symons joined Colchester United on 16 January 2008 following Micky Adams' resignation as assistant manager the previous week. He was appointed as Colchester's caretaker-manager in September 2008 after the departure of Geraint Williams. He led the club to two wins in five games, in the process becoming the bookie's favourite to get the job full time. However, he left the club after Paul Lambert took over as manager.
Symons was subsequently employed by Fulham as Senior Scout and Academy Coach.