A Smithfield statement said: 'John was a great man, full of life and will be sadly missed by his family, friends, colleagues and clients.'
He established the City shop in 1998 alongside longstanding colleague John Kiely, first as part of Chime Communications and later completing a management buyout in 2004.
Chime chairman Lord Bell said: 'He was an affable, intelligent and utterly charming man; we shall miss him a lot.'
He began his career at NM Rothschild and spent two years at Citigate Dewe Rogerson in the 1990s. A staunch supporter of the Conservative Party, he served as a local councillor for Greenwich and was a parliamentary candidate in the 1980s.
There will be a memorial service in May.