Cassin Young was born in Washington, D.C., on 6 March 1894. After graduation from the U.S. Naval Academy in June 1916, he served in the battleship Connecticut into 1919, then spent several years in submarines. During that period, he commanded the submarines R-23 and R-2. During the middle and later 1920s, he served in Naval Communications, on the staff of Commander Submarine Divisions, Battle Fleet, and at the Naval Academy.

During 1931-33, Lieutenant Commander Young served in the battleship New York. He was subsequently Commanding Officer of the destroyer Evans and was assigned to the Eleventh Naval District in 1935-37. After promotion to the rank of Commander, he commanded Submarine Division Seven and had duty at the Submarine Base New London, Groton, Connecticut. When the Japanese attacked Pearl Harbor on 7 December 1941, he was Commanding Officer of the repair ship Vestal, which was badly damaged by enemy bombs and the explosion of the battleship Arizona. For his "distinguished conduct in action" and "outstanding heroism" on that occasion, he was awarded the Medal of Honor.

Promoted to Captain in February 1942, he later was given command of the heavy cruiser San Francisco. On 13 November 1942, during the Naval Battle of Guadalcanal, he guided his ship in action with a superior Japanese force and was killed by enemy shells while closely engaging the battleship Hiei. Captain Young posthumously was awarded the Navy Cross for his actions during the Guadalcanal Campaign, and San Francisco received the Presidential Unit Citation.

The destroyer USS Cassin Young (DD-793), 1943-1981, was named in honor of Captain Young.