[2] Kennedy left to join Liverpool in March 1995 for an initial £1.5 million fee (potentially rising to £2.3 m), making him then the most expensive teenage footballer in British history.

However, opportunities at Anfield were scarce, and he managed just 18 appearances over three seasons, which also saw him loaned to Queens Park Rangers to gain first team action.

Kennedy won promotion to the Premier League with Manchester City in his first season, but the following year saw the club relegated and manager Joe Royle sacked.

When Kevin Keegan took the reins, he sought to rebuild the squad and decided Kennedy was not part of his plans, selling him to fellow second flight club Wolverhampton Wanderers for £2 million.

Kennedy looked set for another promotion in his first season at Molineux, but a groin tear ruled him out of the run-in and the team dropped into the play-off zone in his absence, where they lost to Norwich.

However, the following season saw them achieve the aim of promotion, with Kennedy scoring the opening goal in their 3–0 Division One Play-off final win over Sheffield United.

The Midlands club were unable to remain in the top flight beyond a solitary season though, and soon found themselves with a new manager, with Glenn Hoddle replacing Dave Jones, in late 2004.

With Hoddle departing in Summer 2006, so did Kennedy, after refusing the terms of a reduced contract, he moved to Selhurst Park on a free transfer to play under new manager Peter Taylor at Crystal Palace.

He made his 50th league Cardiff appearance on 5 December 2009, coming on as a substitute for injured Anthony Gerrard in a 1–0 win over Preston North End.

[10][11] He made his international debut on 6 September 1995 in a 3–1 defeat in Austria, but never established himself as a regular player over seven years involved with the national side.

[16] Kennedy managed just 12 first-team games in a COVID-19 pandemic-shortened season, resigning on 12 August 2020 after rejecting the offer of a new contract following the club's relegation to the National League as a result of a points deduction for financial issues.