He came to prominence in the Championship with Reading after a January 2003 move to the Royals and spent 4+1⁄2 years with the club, helping them to earn promotion to the Premier League for the first time ever in 2005–06.

His time at Craven Cottage ended after the club was relegated from the Premier League in 2013–14, and he subsequently joined Stoke City in June 2014 on a free transfer.

He made only 13 Premier League appearances for the club, and finished his career with a two year spell at Brighton & Hove Albion, initially on loan, retiring in 2018.

[9] In January 2003 Brighton and Stoke City both had bids for Sidwell rejected by Arsenal but an offer from Reading was accepted.

[19] Reading failed to make the play-offs in 2003–04 finishing in ninth position with Sidwell playing in 48 matches scoring nine goals.

[22] In the 2004–05 season Sidwell played 47 times, scoring five goals as Reading again miss out on a play-off spot finishing in 7th position.

[27] Sidwell played in 40 matches scoring ten goals and his performances again earned him a place in the PFA Team of the Year.

[34] In total Sidwell played 37 times in 2006–07 scoring four goals as Reading finished in 8th position narrowly missing out on a UEFA Cup spot.

[44] At the end of the season, Sidwell became linked to several Premier League clubs, including Everton, Aston Villa and Middlesbrough.

[45] On 10 July 2008, Sidwell signed a three-year deal with Aston Villa for an undisclosed fee, believed to be in the region of £5m.

[46][47] He made his debut for the club in a pre-season game against FC Zürich, playing the first 45 minutes, in a match which Villa lost 2–1.

[48] Sidwell scored an own goal on his competitive debut for Villa on 19 July 2008 in a 2–2 draw with Odense BK in the UEFA Intertoto Cup.

[51] Sidwell eventually played his first Premier League game for Villa on 26 October 2008 where he came on as a substitute and scored in a 4–0 win away at Wigan Athletic.

[52] On 9 November 2008, Sidwell scored against Middlesbrough but then gifted Tuncay a late goal with a poor back pass as Villa lost 2–1.

[59] Villa had a mixed start to the 2009–10 season as they were knocked out of Europe by SK Rapid Wien but then went on to beat Liverpool 3–1 at Anfield.

[63] Upon his return from injury he was involved in a challenge which left Wolverhampton Wanderers midfielder Adlène Guedioura with a broken leg.

[65] In January 2011, Sidwell was close to a transfer to West Ham United but the move was cancelled as it would have breached the Premier League's 25-man squad rule.

[77] Sidwell did have a poor end to his campaign as he was sent-off on 1 April 2013 against Queens Park Rangers for a late tackle on Armand Traoré.

[79] Fulham made a poor start to the 2013–14 season which saw manager Martin Jol sacked in December 2013 to be replaced by René Meulensteen.

Following the dropping of Brede Hangeland and Scott Parker, and the transfer of Dimitar Berbatov, Sidwell was promoted to the role of captain in February 2014.

[99] Sidwell announced his retirement as a player in August 2018, taking up roles as an ambassador and youth development coach at his final club, Brighton & Hove Albion.