Browne will leave the London authority - one of the best-performing councils - at Christmas to embark on a freelance career.
His agency How Now Communications, of which he is the sole employee, will focus initially on local government, Browne said.
‘I have done district, county and borough PR, and now I want to try something new,' he told PRWeek.
Browne leaves after just under two years at Hammersmith & Fulham, where he leads a team of 15 covering a press office, e-comms, internal comms and a civic newsletter. He was previously head of communications at Bedfordshire - traditionally a less well-regarded council - for three years.
At Hammersmith & Fulham he reports to chief executive Lesley Courcouf.
Challenges for Browne's replacement will include comms around a self-imposed target to reduce council tax. Hammersmith & Fulham has pledged to cut taxes to match those in neighbouring Kensington & Chelsea within four years.
His successor will also lead the council's campaign against the Government's grant-settlement system. The authority, alongside Polish community leaders, claims the Government has underestimated the number of eastern Europeans in the borough - and consequently does not give it adequate funding to support them.
Browne is vice-chair ofthe CIPR's local government group.