When AutoNation Inc. founder W. Wayne Huizenga announced this summer that he was looking for a new CEO, he said he wanted someone with a strong automotive background.

He got what he wanted. Michael Jackson, president of Mercedes-Benz USA Inc. and a former top Mercedes dealer, this month takes the helm at AutoNation, the nation's biggest dealership group.

Mr. Jackson succeeds Mr. Huizenga and Steven R. Berrard. They were AutoNation's co-chairmen. Mr. Huizenga remains as chairman, Mr. Berrard as a board member.

One of Mr. Jackson's top priorities is improving AutoNation's lagging stock performance, a shortcoming which openly irked Mr. Huizenga.