There is life after City Hall — and Mayor Michael R. Bloomberg’s version of it is already looking rather glam.
In the first official appointment for his post-mayoral career, Mr. Bloomberg will become chairman of the Serpentine Gallery in London next year.
The mayor, a billionaire, has made it clear that he plans to focus on philanthropic work, along with national policy issues like immigration and gun control, after his term ends on Dec. 31.
But Mr. Bloomberg has long eyed a return to the more global lifestyle he enjoyed in pre-political days, and London — where he has cultivated deep ties to Britain’s cultural and political elite — is a natural first stop. He owns a home in the tony Knightsbridge neighborhood and has weighed in on the construction of an enormous new London headquarters for his media firm in the city’s financial district.
Mr. Bloomberg is a longtime benefactor of the Serpentine, a prestigious exhibition space for contemporary art in the leafy Kensington Gardens, and he served on its board before pursuing political office in 2001.
As mayor, Mr. Bloomberg is no stranger to serving on prestigious boards: he is the chairman of the September 11 Memorial and Museum and created national groups like Mayors Against Illegal Guns. But he stepped down from formal positions with several cultural institutions when he entered public life.
His chairmanship of the Serpentine was disclosed this week at the gala opening of the museum’s newest gallery, partly designed by the famed architect Zaha Hadid and partly paid for by Mr. Bloomberg himself.
He was in London on Tuesday and attended the event, where he spent the evening reconnecting with his British coterie, including the Serpentine’s director, Julia Peyton-Jones, a close friend; Boris Johnson, the mayor of London and a close political ally; and George Osborne, the chancellor of the exchequer.
Graydon Carter, the editor of Vanity Fair and another longtime friend of the mayor, hosted the event with Mr. Bloomberg.