Bright Young Things Communications will specialise in youth consumer PR for the public and voluntary sector.
It will also offer a matching service for consumer brands that want to link with charities to run cause-related campaigns.
Beatbullying is the agency's launch client, but the start-up has just signed a contract with People & Planet, the high profile student campaigning network.
The agency has been briefed to run a press office, supporter and member campaigns and raise its media profile.
Cowley claimed his in-house charity comms experience gave him the edge over rivals. He was keen to stress the benefits of one agency delivering the same campaign across social networking platforms and traditional media.
'I feel very strongly that it is the role of the client's PR agency to deliver online strategies and not the role of advertising and marketing agencies,' he said. 'PROs have always developed content that influences editorial, so we will continue to do this but in the user generated editorial world.'
Bright Young Things currently has two full-time staff - Cowley and account executive Chris Polick.
The agency will use two freelancers to produce content for online virals. They are Osama Chami, who has experience in music video production, and former MTV producer Lorraine Warner, who will produce all video content.
Cowley has worked at Beatbullying for the past two years.
Before Beatbullying he was an account director at Geronimo Communications and at August One Communications for four years.
Following Cowley's departure, Beatbullying's comms officer Richard Piggin has been promoted to comms manager.