A third of the 2,275 people currently working at the park, being built for the 2012 Olympics, lived locally, the study also showed.
Up to 15,000 construction workers will be employed at the peak of the contract in 2009/10, according to the Olympic Delivery Authority.
Mr Brown said: "The job figures and the ODA employment and skills strategy published today show that the construction of the site can be the catalyst for lasting social and economic change."
The ODA today announced plans to recruit 2,000 trainees, apprentices and work placements on the Olympic Park and other London 2012 venues, including a programme aimed at getting women into construction jobs.
ODA chairman John Armitt said: "As the figures we are publishing today show, a lot of this work has been carried out by people previously out of work, demonstrating that this regeneration is more than just physical transformation, it is also about social and economic change.
"London 2012 will be the 'Regeneration Games' for these reasons and we want the Games to leave a real long term employment and skills legacy for local people and UK construction."