Lee was signed from non-league Enfield for £15,000 on transfer deadline day 1997 after impressing in trials with the Canary Reserves. He was first spotted by Dave Stringer playing for Enfield Reserves against Norwich's A team in the Essex and Herts Border Combination. He made his debut for Norwich against Bury in November 1997 but broke his ankle just 15 minutes into his second game (against WBA). He recovered to make another 2 appearances in the 1997/98 season.

Lee won his first England Under 21 cap coming on a late substitute against France in February 1999. Starting to make an impression on the game, the inevitable result was transfer speculation. On 12th March 2000, the Sunday People reported that Norwich "could cash in on Lee Marshall... Wolves, Charlton and Huddersfield are all looking at a player rated at £500,000". The speculation arose again in the autumn with the 19th November edition of The People suggesting that Leicester might make a move for him. Fulham and Portsmouth were said also to be interested.

Failure to accept Norwich's offer of a new contract saw Lee placed on the transfer list on the last day of November 2000. The Sunday tabloids suggested on 28th January 2001 that Leicester were keen but would face competition from Spanish sides Real Vallecano and Real Oviedo. On 21st March 2001, Norwich finally cashed in on Lee rather than lose him to a Bosman style tribunal in the summer. Leicester City signed Lee for £600,000 with Marshall linking again with the likes of Darren Eadie and Peter Taylor who had capped him for the England Under 21s.

In July 2002, Lee almost joined Premiership new boys West Bromwich Albion as relegated Leicester attempted to cash in on some of their assets. However he failed to agree terms with Megson's Baggies. The deal resurfaced in early August and Lee transferred for £700,000 on 14th August 2002. Whether Lee will stay with the Baggies following their relegation in April 2003 remains to be seen. Speculation has already begun on the Planet Football site that Lee might return to Leicester along with teammate Andy Johnson

In September 2003, Lee was transfer-listed and made available for loan - with his name circulated to all Premiership and Division One sides. Barnsley made an offer on 13th October to loan him but Lee rejected it preferring not to drop into Division Two. Out of favour at the Hawthorns, Lee joined Hull City on loan towards the end of January 2004. What his future holds now West Brom have been promoted to the Premiership is questionable.

Suffering a broken fibula and tibia whilst with Hull, Lee never fully recovered and retired through his injuries on 22nd April 2005.

Lee lives in Cuffley, Hertfordshire and in September 2005, began helping out at nearby Minerva League side Broxbourne Borough V&E with coaching and advising players.