The former UBS banker, who had been acting CEO since February 1st, was widely expected to take up the post.
His appointment, effective April 1st, was approved by the federal government following the unanimous agreement of FINMA’s board of directors.
Branson, 45, who headed FINMA’s banks division after joining its executive board in 2010, succeeds Patrick Raaflaub, who announced in January that he wanted to step down to seek "new challenges".
The graduate of Trinity College Cambridge, where he studied mathematics, began his career with consultants Coopers & Lybrand before moving to Credit Suisse in London, where he became head of the customer support department.
Branson later joined SBC Warburg before becoming CEO of UBS Securities Japan in 2006, and was later appointed chief financial officer in 2008 of the wealth management and Swiss bank division of UBS, Switzerland’s largest bank.
He rode out calls from some Swiss politicians to quit FINMA at the end of 2012 when UBS’s Japanese unit pleaded guilty to wire fraud as part of a settlement with the US Department of Justice.
Branson was in charge of the unit from 2006 to 2008 but he stepped aside from FINMA’s investigation of the fraud case, involving bids to manipulate various benchmark rates.
His appointment came amidst griping in some Swiss media that the CEO job should be held by a Swiss citizen.
But Ann Héritier Lachat, FINMA’s chair, said Branson had the right credentials.
"While in charge of banking supervision, Mark Branson has shown that he is well capable of becoming FINMA CEO", she said in a statement.
"As a member of the executive board, he has shaped a number of important projects in all supervisory areas, as well as in international committees,” she said.
“He is fully acquainted with FINMA's daily business and its long-term objectives.”
FINMA, created in 2007, resulted from the merger of three authorities — the Swiss Federal Banking Commission, the Federal Office of Private Insurance and the Anti-Money Laundering Control Authority.
But its birth occurred in a tense atmosphere, with UBS needing a bailout from the federal government and the Swiss National Bank after sustaining massive losses linked to the global financial crisis.