Born in Monaghan, Douglas first joined Blackburn Rovers after having been a trialist at Celtic and made his debut against West Ham United in the League Cup on 31 October 2000.

[2] Ironically Blackpool were his next loan destination, joining them for three months, where he made a significant impact, playing in 16 league games and scoring three goals.

Not soon afterwards, Graeme Souness, manager of Blackburn Rovers, found his side struggling near the bottom of the Premier League and missing a left midfielder due to injuries and inadequate transfer dealings.

[3] Douglas had shown his potential as a utility squad player for Blackburn and Rovers awarded him a three-year contract.

However, manager Souness departed to Newcastle United and under new boss, Mark Hughes, Douglas soon fell down the pecking order and moved out on loan to Gillingham of the Championship, along with Rovers' youngster, Jay McEveley.

He had played numerous matches as Leeds captain previously due to injuries to Nicholls, Shaun Derry and Gary Kelly.

Douglas was forced to sit out the rest of the season when he received his 15th yellow card in the defeat at Colchester United.

Douglas' played in a more unfamiliar position of right back as Leeds reached the playoffs again, only to be knocked out the competition when they lost 2–1 on aggregate to Millwall.

[12] Douglas missed a home match with Hartlepool United, two away trips to Norwich City and Tranmere Rovers and the visit of Conference South side Woking in the FA Cup First Round.

Douglas scored with a volley into the top corner from 25 yards out against Sheffield Wednesday in a 3–1 defeat, his only goal for the club.

[16] His first goal arrived at Rotherham on 7 November in a 5–2 victory and Douglas followed that strike up in the next game at home to Wolves in a 2–2 stalemate.

[18][19] Having already featured in a number of friendlies, Douglas made his competitive debut for Ireland in the European Championship Qualifier against the Czech Republic on 11 October 2006, starting in central midfield alongside Lee Carsley.