After an impressive youth career in his native Ireland with Dublin-based Belvedere and St Patrick’s Athletic, Fleming's form earned him a move to Swindon Town in March 1989.
But he didn’t play a game for the Robins and returned to Ireland, where he was a league winner with St Patrick’s. He also played in both the European Cup and UEFA Cup for the Dublin side.
Curtis returned to England again in the summer of 1991 when Lennie Lawrence paid £50,000 for his services - and this time he was here to stay.
The defender was a Boro player for a full decade and made over 300 appearances, won three promotions and was part of the squad that reached the League Cup final twice and the FA Cup final in 1997.
Curtis was handed a testimonial match by the club at the start of the 2001 season when Bilbao were the visitors.
It was during his time at Boro that Curtis made his full debut for the Republic of Ireland, against the Czech Republic in Prague in 1996. He went on to win 10 caps for his country.
Curtis first left Boro in November 2001 when he joined Birmingham City on loan. The following month he moved to Crystal Palace on a permanent basis and spent two-and-a-half seasons with the Selhurst Park club where he was made club captain.
He returned to the north east in the summer of 2004 to join Darlington where he made 28 appearances for the then League Two club. After a brief return to Ireland, his career continued on a semi-professional basis, where he played for Billingham Synthonia in the Northern League.
After stepping into the dugout as part of the coaching staff with Palace and Bolton Wanderers alongside Dougie Freedman, Darlington under former teammate Craig Hignett and latterly QPR with Ian Holloway, Fleming returned to Boro as a first team coach under Tony Pulis in February 2018.
Fleming left Boro's coaching staff shortly after Pulis in the summer of 2019.