Ms Hoey will aim to encourage more young people to play sport
London's 2012 Olympics must benefit the entire capital by increasing sport participation, Boris Johnson has said.
The mayor said the east London-based games would be part of a "boom" in new sporting activity across London.
Mr Johnson also confirmed the appointment of Labour MP Kate Hoey as his Commissioner for Sport.
Her unpaid role will be to encourage more young people to play sport. Ms Hoey previously said London did not "deserve" to host the 2012 games.
In 2004 Ms Hoey, who was sports minister from 1999-2001, criticised the government's decision to spend £30m on its bid to host the Olympics.
But on Thursday she said her previous comments would not prevent her from working with Olympic organisers.
"I'm sure we will all be able to work very hard together because I'm determined to really get sport much higher up the priority list of both government and London government," she said.
"Sport crosses all political divides and I am happy to play my part."
Ms Hoey will not represent the mayor on the board of the London Organising Committee for 2012, however.
Mr Johnson added that he would ringfence London Development Agency money for sport.
He also said sporting facilities across the capital would be protected in his forthcoming London Legacy Plan for Sport.
"We've got to make sure that the benefits from the Olympics and the sporting enthusiasm that they generate are felt right the way across London," he said.
Mr Johnson announced his intention to appoint Ms Hoey before he was elected as mayor.
At the time Liberal Democrat mayoral candidate Brian Paddick said: "Kate Hoey is bonkers - they make a perfect couple."