During World War II, Hamlin was an intelligence officer in the Navy and retired as a Lieutenant Commander in 1945.
From 1946 to 1951, Hamlin served as Executive Secretary to the Republican State Central Committee of California.
His duties were to keep various segments of the Executive Branch and the Republican National Committee aware of each other's activities.
He compiled background reports on the large agencies, current administration problems, pronouncements and goals.
The purpose of the Committee on Government Activities Affecting Prices and Costs created by Executive Order 10802, January 23, 1959, was to provide a central mechanism in the Federal Government to follow the current activities of the Federal agencies to see whether they were being conducted, insofar as possible, in line with the need for reasonable stability of prices and costs, and to ensure that the Federal Government was not contributing to the nation's inflationary problems by the way in which it conducted its business.