Her brief in the unpaid role is to increase grass roots participation and access to sporting opportunities across London.
Ms Hoey’s key responsibilities will be to oversee the production of the London Legacy Plan for Sport, which the London Development Agency (LDA) have already started working on.
A former Northern Ireland high jump champion and minister for sport, Ms Hoey was described by Liberal Democrat mayoral candidate Brian Paddick during the campaign as “bonkers".
Mr Johnson paid tribute to Ms Hoey. He said: “I am absolutely delighted to be able to announce that Kate is going to be helping me to rebuild sport provision in London. She made it perfectly clear that she cares deeply about providing young people in London with access to good sports facilities."
Other mayoral appointments include the former Conservative transport minister Stephen Norris joining the boards of LDA and Transport for London, and Conservative assembly member Brian Coleman who becomes chairman of the London Fire & Emergency Planning Authority.
Former Greater London Council transport chair Dave Wetzel, who launched the Fares Fare initiative for the scrapped body, has resigned as vice chair of Transport for London.