Niall Quinn said on Monday that he is to step down from his role as international development director at Premier League side Sunderland to concentrate on his family and other business interests.
"I have had the most amazing six years and it gives me a huge sense of pride to see where Sunderland is today," said the former Republic of Ireland international, who has also acted as chairman of the northeast side.
Sunderland are currently in ninth position in the league and last weekend beat Arsenal 2-0 to progress to the quarter finals of the FA Cup, raising hopes among fans at the Stadium of Light of a return to Wembley and silverware.
Quinn, who played for Arsenal and Manchester City as well as Sunderland, headed an Irish consortium that backed the Black Cats' return to the Premier League after relegation to the Football League in the 2005-6 season.
He took over as chairman and persuaded the US-based Irish-American businessman Ellis Short to come in, leaving him free to develop the club's interests abroad.
The former striker said the measures he had introduced, as well as the appointment of Martin O'Neill as manager, would stand the club in good stead for the future.
"Everything is in place for Sunderland to really make a statement, which was always my aim," he added.
"I am now looking forward to spending more time with my family and exploring business interests away from football," he said.
Short described Quinn in a statement as a "Sunderland legend" and vowed to build on the foundations he had laid.