David Dyson, finance director at Lookers, is leaving the business for personal reasons.
The board today announced that Robin Gregson will take up the role, while Dyson acts in a consultancy role during a handover period.
Dyson had been with Lookers for 17 years.
Gregson was previously group finance director of CD Bramall between 1998 to 2004.
Ken Surgenor, chief executive, said: "I would like to thank David Dyson for his contribution to the company's development over the last 17 years.
"The board identified Robin Gregson as uniquely well qualified to lead our finance function given his experience of the motor sector and expertise in arranging financing structures.
"Robin will complement the existing board and will work closely with me and my fellow directors to further develop the business."