 His final active duty commands, culminating 35 years of service in the Marine Corps, were as the Supreme Allied Commander Atlantic (SACLANT) for NATO and as Commander-in-Chief for the U.S. Atlantic Command (CINCUSACOM) (1994–1997).Sheehan was born on August 23, 1940, in Somerville, Massachusetts.The son of Irish immigrants, he is one of seven children.