Troughton, whose resignation from Harrison Troughton Wunderman was revealed in Campaign last month, becomes the UK chairman of Red Cell Response.
He will work with Miles Murphy, the Red Cell Response chief executive, and report to Amanda Walsh, Red Cell's European chief executive.
Troughton is said to have grown frustrated at the "corporateness" of the Wunderman organisation.
Troughton said: "Red Cell is a dynamic network and there are many growth opportunities ahead of it."
Red Cell Response is the rebranded name of Perspectives Red Cell, which was relaunched in June as part of efforts to upgrade its strategic and creative offering and align itself better with sister agencies.
HTW is currently looking for Troughton's successor.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum here.