|Full name||Dean Brennan|
|Date of birth||17 June 1980|
|Place of birth||Dublin, Republic of Ireland|
|Height||5 ft 9 in (1.75 m)|
|Playing position||Winger / Attacking midfielder|
|2003–2004||→ Hendon (loan)||4||(2)|
|2007||Hemel Hempstead Town||19||(1)|
|2010–2011||Hemel Hempstead Town|
|2010||Hemel Hempstead Town (Caretaker)|
|2012–||Hemel Hempstead Town|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
Brennan began his footballing career at Sheffield Wednesday but despite impressing at youth and reserve levels, he never made a first team appearance for the Owls. After being released by Wednesday in the summer of 2000, Brennan came home and went on trial at Bohemians. He made two appearances for the club in the FAI Super Cup but Roddy Collins decided not to sign the midfielder.
Brennan then went on trial at Luton Town and this time it was more successful, earning a two-year contract at Kenilworth Road. He made his debut for the club in a 2–1 defeat at Wigan Athletic soon after. However, he never became a regular at the club and in 2002 moved to Hitchin Town.
Luton would prove to be his last taste of league football as he drifted around the non-League scene with spells at Stevenage, Grays Athletic, Lewes, AFC Wimbledon, Cambridge City, Chesham United and Hemel Hempstead Town in the following years. In his brief spell with Wimbledon he earned the nickname "the Irish Beckham", a reference to his crossing ability.
In August 2009, Brennan signed for Spartan South Midlands Football League Premier Division side Aylesbury. In 2010, he rejoined Hemel Hempstead Town, and in March after the sacking of manager Gary Phillips, he was appointed as caretaker manager at the age of just 29.
Brennan began a second spell with Dunstable Town at the start of the 2011–12 season. He joined as player/coach and managed the team in cup ties. In May 2012 he rejoined Hemel Hempstead Town this time as manager. He helped the Tudors to their highest ever finish (4th in Southern League Premier Division) this meant that they had qualified for the playoffs. They reached the final against Gosport Borough F.C., where they drew 2-2 which sent the game to penalties which was lost 5-4.
- "Luton Town: Dean Brennan". Luton Town F.C. Retrieved 6 February 2010.
- "Club guide". The Daily Telegraph (London: Telegraph.co.uk). 8 August 2002.
- "Player profiles: Dean Brennan". AFC Wimbledon. Retrieved 6 February 2010.
- "Aylesbury Football Club: Dean Brennan". Aylesbury F.C. Retrieved 6 January 2010.
- "Brennan Back at Tudor's Helm". NonLeagueDaily.com. Retrieved 24 May 2012.