Beginning his career at Manchester United, he was tipped as a huge star for the future, being part of their FA Youth Cup-winning team in 1995 (when he was still only 16 years old and in his final year of secondary school) and turning professional in 1997.

He proved himself as competent at right-back and centre-back, but was unable to claim a regular first team place at United and went to Barnsley on loan during the 1999-2000 season.

Blackburn Rovers manager Graeme Souness was impressed by the young defender, and managed to prise Curtis away from Manchester United during the summer of 2000.

During the next season he was an ever present as Blackburn were promoted to the Premiership as Division One runners-up.

By this time he had also represented England at youth, Under-21 and 'B' level and was being hailed as a future England captain.

However, his 2001-02 Premiership campaign was dogged by injury, limiting him to just 10 league appearances. He failed to regain his regular starting place, and spent the second half of the 2002-03 season on loan to Sheffield United.

At the end of the season he was released by Blackburn on a free transfer, and was signed by Leicester City (newly promoted to the Premier League).

However, Curtis's spell at Leicester was unsuccessful, and after making just 17 appearances, he was transferred to Portsmouth in February 2004, again on a free transfer.

After failing to win a regular starting place in the side, at the start of 2004-05 he was loaned to Preston North End. Upon his return to the club at the end of October, he spoke of his determination to win a regular place at Portsmouth and get his career back on track.

However, he made only 5 appearances under Harry Redknapp, and failed to play at all under his successor Velimir Zajec. In January 2005, Curtis was transferred on a free transfer to Nottingham Forest, initially on a short term contract before signed a 2-year deal.

There he established himself as first choice right-back up to the end of the 2007 season, when Forest missed out on promotion to the Football League Championship. Shortly afterwards, Nottingham Forest announced that they would not be offering him a new contract, and that he would therefore be free to leave after 30 June 2007.

Curtis signed for Queens Park Rangers on a free transfer on 30 June 2007. However, his period at the club was unsuccessful and his contract was terminated by QPR on 12 December 2007.

Following a trial with Notts County, Curtis joined Worcester City in January 2009 and signed for Conference National side Wrexham in February.