Despite having been turned away by Watford's Academy after an unsuccessful spell, Young endeavoured to improve himself as a player and was eventually offered a professional deal by the club. The 18-year-old was handed his first team début under Ray Lewington in September 2003, scoring as a substitute against Millwall.He achieved five substitute appearances that season, scoring three goals, and made his first start for the club in the League Cup. Young came to prominence in the 2004–05 season, playing a part in 34 of Watford's league matches as they struggled to survive in the Championship. Although he failed to find the net, his performance during this season earned him the club's Young Player of the Season award.
On 18 January 2007, Aston Villa had an £8 million offer (rising to £9.75 million with add-ons), accepted—the club's record transfer fee. This allowed manager Martin O'Neill and the Aston Villa board to discuss personal terms with the player. Two days later O'Neill confirmed the player had agreed to join the club. Young underwent a medical on 21 January and the signing was confirmed on 23 January 2007.On 31 January, he scored in his debut for Villa at St James' Park against Newcastle United, but Villa went on to lose 3–1. Ashley Young started the 2007–08 season well, receiving several Man of the Match awards. The good start was highlighted by his call-up to the England Squad.
On 23 June 2011, Young completed a move to Manchester United, having passed a medical the day before. He signed a five-year deal with the Manchester club for an undisclosed fee.He made his debut on 13 July in a 4–1 friendly win against American club New England Revolution, playing 67 minutes on the right wing before being substituted..On 7 August 2011 he played a FA Community Shield match against Manchester city and won his first trophy with Manchester United.
Manchester United's Ashley Young: Looking Back, Looking Forward