Dean Sinclair is a midfielder from Luton who was a aproduct of Norwich's centre of excellence at Potters Bar which has produced many fine players, not least Darel Russell, whom Sinclair has often been compared to. Sammy Morgan said: "Sinclair is very similar to Darel. It will be interesting to see how he develops physically. He's very strong, a good runner with the ball and he will keep learning. He's always been the best player in his team so he is inclined to overdo it. Darel was like that. He's got to learn when to release the ball because he wants to do everything. But having been under the eyes of the London clubs we are delighted to have him with us." Dean was the last schoolboy to come through the Potters Bar centre

As a Second Year Academy Scholar at Carrow Road, he played in reserve matches and pre-season friendlies throughout 2002/03. He made his first team debut on February 25th 2003 at Gillingham (a 1-0 defeat) when Norwich's midfield had been decimated by injury. He had a good performance against an experienced midfield. He signed a two year professional contract at the beginning of May 2003.

Following Norwich's promotion to the Premiership, the cub announced on 26th April 2004 that they would no longer be keeping Sinclair on their books. He had not made a single appearance during 2003/4 and so was unlikely to see first team action in the Premiership. By releasing him in April, it would give him a head start in finding a new club.He trained with Wimbledon and played for their reserves on 27th April against Charlton. Dean was later linked with a move to Swindon.

Dean eventually joined Conference side Barnet on 12th August 2004 and made hus debut two days later against Forest Green. His form in midfield as Barnet took a clear lead at the top of the Conference saw him called up into the England National game XI in mid-October 2004. Barnet won the Conference title in 2004/5 and returned to the Football League. He was also called up into the England non-league side for the Four Nations tournament against Wales, Scotland and Ireland in May 2005. England were victorious in this tournament with Dean playing in all three games.

Dean's form during the 2006/7 season saw speculation that linked him with a move to fellow London sides Crystal Palace, Millwall and Leyton Orient - as well as to Championship teams Norwich and Leicester. This continued into the 2007/8 close season with Leicester, QPR, Sheffield Wednesday, Derby County, and former club Norwich City linked with signing him. After a successful trial, Dean signed for Charlton Athletic for a fee of £125,000. He had made 125 appearances for Barnet, scoring19 goals.

Dean was loaned to Cheltenham for a month from 5th October 2007 and made his debut the following day in a 1-1 draw with Oldham. Although he returned to Charlton he was loaned back to Cheltenham in August 2008

In January 2009, Dean was loaned to Grimsby for a month. This was extended for a further month in mid-February.

On 26th November 2009, Dean was loaned back to Barnet.

Dean joined Grimsby on loan on 28th January 2010. This was the second time that Charlton had loaned the midfielder to the Mariners. He was one of six signings made by Grimsby during the transfer window. However this did not prevent them from avoiding relegation to the Conference.

Sinclair was released by Charlton at the end of the 2009/10 season and was immedialely linked with signing for Grimsby. After having a knee operation, he signed for Grimsby onb a short term contract at the beginning of December 2010 and made his debut for them in a 3-0 win over Redditch in the FA Trophy.

He was released by Grimsby at the end of the 2010/11 season. He had a brief spell with Zema Abbey's Arlesey.

On 17th February 2012, Dean signed for Lowestoft along with Kirkley's Nathan Stone.

On 7th August 2012, Dean signed for Conference side Woking on a short-term contract.

Dean moved to Sutton United (Conference South) on 19th January 2013. He had made 21 appearances for Woking.

He moved to league rivals Eastbourne Borough in the summer of 2014. He moved to Hampton & Richmond Borough the following summer.