Dennison held numerous commands in the United States Navy, including submarines, destroyers, and the USS Missouri (BB-63). Truman twice sailed on the Missouri while Dennison commanded it. He was a naval aide to Harry Truman from 1948 to 1953.[3]
Arleigh Burke, a former classmate of Dennison's who would one day become Chief of Naval Operations, found his career on the brink of ruin, following the Revolt of the Admirals. At the request of Dennison, Truman became involved. As a result, Burke's career stayed on track.[4]