"Sandy Weill is an icon in the financial services sector, someone who has been at the forefront of change throughout his career," Hamilton CEO Brian Duperreault said in a statement.
Hamilton acquired SAC Capital's reinsurance business last year, clearing the way for Steven A. Cohen's hedge fund to convert into a family office.
Duperreault "has run businesses very successfully in all parts of the insurance industry," Weill said in a statement. "I look forward to working with the Board on the opportunities and challenges that lie ahead."
Weill retired from Citigroup in 2006. He was instrumental in the merger of Travelers Group and Citicorp to create Citigroup in 1998, ushering in the era of U.S. banking conglomerates.
-By CNBC's Karma Allen. Follow him on Twitter @iam_karma .
image: © David Shankbone