Former Observer Whitehall editor Revill started her comms career as strategic comms adviser to Alan Johnson, when he was health secretary.
Revill starts her new role at London Councils next week.
She said: ‘London Councils’ policies and programmes make a real difference to Londoners, and I want to help the organisation reach a wide audience, both inside Westminster and right across the capital.
‘There's never been a more important time to communicate the value of the work carried out by London's boroughs.’
At GSK, Revill was responsible for managing news flow and media coverage around products and pipeline.