The development, which included building a stadium for a local football team in Chislehurst, south-east London, community sports pitches and two four-storey residential blocks, had been approved by Bromley Council.
But Mayor Khan said the plan for the Flamingo Park Club would cause significant harm to an area of much needed open green space and he was also concerned that it included no affordable housing.
The mayor has also used his planning powers to give consent to several schemes to boost housing supply in the capital and said he was keen to work with boroughs, developers and housing associations to build the 50,000 homes London needs each