Robert Harwood-Matthews, the client services director at TBWA\London, is replacing Neil Griffiths as the chief executive at BDH\TBWA in Manchester.
Griffiths left the agency last week along with the long-serving managing director, Carol Smith.
The pair left the agency in a mutual agreement with Martin Kemp, the BDH chairman.
He said: "This is a natural management progression and the departure of Neil and Carol has nothing to do with the Morrison's result. We just agreed that we all had to move in different directions."
The agency lost the £37 million Morrison's business, its biggest account, to Delaney Lund Knox Warren & Partners in August.
Kemp added: "Robert's arrival signals an exciting new era for BDH and I am confident his dynamism and strategic input will be beneficial to the whole TBWA\Manchester group and our clients alike."
Suzie Shaw, at present the new-business director at TBWA, will replace him as client services director.
Harwood-Matthews said: "I am honoured to be asked to lead the North's finest ad agency. BDH\TBWA is an agency with tremendous creative talent and produces great work for a strong client base. I am also excited by the enormous potential for growth."
Harwood-Matthews most recently worked on the upcoming interactive launch of the Sony PlayStation 3.
Before joining TBWA in 2002, he was the director-in-charge and a member of the board at JWT, his second spell at the agency, working on accounts such as NTL and Nestle. Before this, he was an account director at Publicis. He began his career in 1993 at Young & Rubicam as a graduate in the media department before joining JWT for the first time.