He moved at the start of the 1986-87 season to Watford, but only spent a season there before moving on to Arsenal for £200,000. Richardson succeeded Graham Rix on the Arsenal left wing, before moving over to the right for Arsenal's 1988-89 title-winning season to cover for the injured Paul Davis. Now a Championship winner at two different clubs, Richardson continued to be a regular the following season at Arsenal; however, he never totally got on with Gunners manager George Graham, and he was transferred to Real Sociedad for £750,000 in the summer of 1990. He made 121 appearances for Arsenal, and scored 8 goals.
Richardson's time at Real was short and relatively unsuccessful. He moved back to England in the summer of 1991, signing for Ron Atkinson's Aston Villa for £450,000, and was an ever-present in his first season at the club. Richardson became Villa's captain, and led the club to runners-up spot in the inaugural FA Premier League season of 1992-93 and a League Cup final win over Manchester United in 1994. While at Villa, he also won his one and only cap for England, a 5-0 friendly victory over Greece on May 17, 1994.
Richardson followed his old boss Atkinson to Coventry City in 1995, and spent the next two and a half years at the Sky Blues repeatedly fending off relegation under Atkinson and his successor, Gordon Strachan. He left Coventry in September 1997, and had spells at Southampton, Barnsley and finally Blackpool. Richardson retired from playing in 2000, his career finishing on a low after Blackpool were relegated to the Third Division in his final game.
After retirement, Richardson took up coaching, becoming youth team manager at Sunderland, and then Carlton Palmer's assistant at Stockport County in 2001. He returned to Sunderland as reserve team coach in 2004 and became first team coach following the club's takeover by a consortium headed by Niall Quinn. Incoming manager Roy Keane initially retained Richardson in this capacity before replacing him with former Manchester United coach Neil Bailey. Richardson is currently Sunderland's reserve team coach.