Robert Porter Patterson, Sr. was the United States Secretary of War under President Franklin Roosevelt and the United States Secretary of War under President Harry S. Truman from September 27, 1945 to July 18, 1947.

After graduating from Union and Harvard Law School, Patterson practiced law in New York City. He served in the U.S Army during WWI, reaching the rank of major, and received the Distinguished Service Cross for heroism in France.

President Hoover appointed Patterson as a judge of the United States District Court for the Southern District of New York in 1930. And was then promoted by President Roosevelt to the United Stated Court of Appeals for the Second Circuit. Fifteen months later, he left the bench to become the Assistant Secretary of War and then Secretary of War in 1940 under Roosevelt. He was instrumental in the mobilization of armed forced before and during WWII.

In 1945 Patterson was appointed Secretary of War by President Truman. He advocated for the unifying of the armed services, the National Security Act of 1947, and the the creation of the Tuskegee Airmen.