Cilla Snowball, the acting vice-chairman of Craik Jones, has no plans to replace Jackie Stevenson, the managing
director who resigned in December to found a start-up alongside the Abbott Mead Vickers BBDO managing partner George Bryant, and Jason Fretwell, an AMV senior creative.
Welsh will aim to reinvigorate the direct marketing shop, which has suffered a series of blows in the past 12 months.
As well as losing its chief executive and managing director, David Watson, the chairman and last remaining founding partner, the digital executive creative director, Jonas Lembke, and Mark Buckingham, a creative director, all announced their departures last year.
In November 2005, Welsh, the former business development director at Claydon Heeley, was promoted to managing director following the departure of Nigel Jones, Claydon Heeley's chief executive.
Apart from a seven-week interlude when Richard Madden took the helm as the chief executive, Welsh has been responsible for the day-to-day running of Claydon Heeley.
Snowball said: "Mike understands our brand and our creative ambition."
The chief executive of Zulu, David Eastman, added: "We are happy Mike is staying in the wider Omnicom family."