Peter Hearn has been promoted to CEO of Willis Re, where he will oversee the unit's global efforts.
Grahame Millwater, previously chairman and CEO of Willis Re, remains as chairman.
The reinsurer said Hearn, a 28 year veteran of the reinsurance industry, has made a consistent contribution to the unit's growth in North America since joining Willis Re in 1994.
He was named president of the global broker's US reinsurance operations in 2002 and promoted to CEO of the unit in March 2005.