Niall began his career at Highbury, making his League début for Arsenal in 1985. He enjoyed one full season (1986/87) in the Gunners side and earned a Littlewoods Cup medal before dropping out of the side. In March 1990, he was transferred to City for £800 000.
In his first full season he was City's top scorer with 22 League and cup goals. He picked up a cruciate ligament injury in November '93 that caused him to miss the World Cup finals. He was back in City's side the following season but never really established himself as a regular under Alan Ball. Niall was City's best player in the 1996-97 pre-season games, the only one scoring regularly and looking to be back at his best. It was therefore a very unpopular decision when, as one of his last acts as City manager, Alan Ball sold Niall to Sunderland at the start of the season.
At Sunderland Niall linked up with former City Manager Peter Reid and he served the club with perfection the next 6 years. His partnership with Kevin Phillips up front helped Sunderland secure a high position in their return to the Premiership. After his playing days was over he continued at the club in a coaching role.
May 2002: Republic of Ireland striker, Niall Quinn is giving away the proceeds of his testimonial match to charity, it's reported. It's expected the Sunderland forward's match against the Republic in May will raise £1m for hospital equipment in Britain and Ireland. The 35-year-old will use some of the money from the game to buy school books in Africa and Asia. The bulk of the money is expected to go to hospitals in Sunderland and Niall's home city of Dublin, reports The Sunday Times. He said his first visit to Great Ormond Street's children hospital when he was a teenager at Arsenal, had awoken him to the suffering of children. The newspaper says fans will not be segregated into rival camps and players will not receive champagne or Rolex watches. Instead they will be given an envelope from a child thanking them for paying for his or her education for the next five years.