He enlisted in the United States Naval Reserve on 26 February 1941, was appointed Aviation Cadet on 3 April 1941, and was commissioned as an ensign on 20 October 1941.

On 12 November 1941 he was assigned to Scouting Squadron 5 on board the aircraft carrier USS Yorktown as a Douglas SBD Dauntless dive bomber pilot.

Kinzer, in company with fast transport USS Scribner (APD-122), continued this pattern while dodging Japanese kamikaze suicide planes during patrols and antisubmarine-screen duty in the Okinawa campaign until she departed on 15 July 1945 with a convoy headed for Guam.

Completing overhaul, Kinzer departed San Pedro on 6 September 1945, disembarked passengers at Pearl Harbor, Guam, and Ulithi Atoll, and arrived at Manila on Luzon in the Philippine Islands on 13 October 1945.

Kinzer cleared Qingdao on 25 April 1946 for the United States, calling at Guam and Pearl Harbor en route and arriving at San Pedro on 17 May 1946.

She was commissioned by the Republic of China Navy as a frigate, serving as ROCS Yu Shan (PF-32) and receiving a second single 5" turreted gun aft.