A managed care company has filled a high-level post.

Aetna Inc., Hartford, has named Mark Bertolini president of the company.

Ronald Williams, who has been Aetna’s chairman, president and chief executive officer, will keep the chairman and CEO titles, Aetna says.

Bertolini has been an executive vice president in charge of business operations at Aetna. He began working for the company in February 2003 as a senior vice president of specialty products.

Bertolini previously worked for other managed care companies, including CIGNA Corp., Philadelphia.

Bertolini has a bachelor’s degree in business from Wayne State University and a master’s degree in business from Cornell University.