Hartford Financial Services Group Inc (HIG.N) said Chief Executive Liam McGee underwent a successful brain surgery to remove a small tumor.
McGee, 57, had displayed no symptoms previously, and post-surgical tests indicated that he was cancer-free, the insurance company said.
"In an abundance of caution, the doctors and I have agreed on a low-dose chemotherapy and radiation treatment and we expect minimal side effects," McGee said in a statement.
McGee, who was working from home, will return to office on Monday. The company declined to provide additional details on the surgery.
Hartford hired McGee from Bank of America Corp (BAC.N) in 2009, four months after the insurer was forced to accept a $3.4 billion government bailout due to bad bets on bonds. McGee headed Bank of America's consumer and small business banking unit for five years.
McGee restructured the 200-year-old insurer in 2010 into three main units -- consumer markets, commercial markets, and wealth management -- to reduce complexity of the business.
The insurer underwent another round of restructuring last year under pressure from famed hedge fund manager John Paulson. Paulson screamed at the management on an earnings call in February to do something "drastic" to boost its industry-low valuation.
Hartford has since sold off its life insurance, retirement plan and individual annuities units.
Shares of the company closed at $23.90 on the New York Stock Exchange on Friday.
(Reporting by Jochelle Mendonca in Bangalore; Editing by Sriraj Kalluvila)