Philip Kirkwood was born on April 15, 1921, in Wildwood, New Jersey. After graduating with a bachelor's degree from Duke University, he entered the Naval Aviation Cadet Program on February 23, 1942, and was commissioned an Ensign in the U.S. Navy and designated a Naval Aviator on March 10, 1943. After completing carrier training and F6F Hellcat transition training, LtJg Kirkwood served as an F6F-3 and then F4U-1D Corsair pilot with VF-10 at NAS Seattle, Washington, and NAS Atlantic City, New Jersey, and aboard the aircraft carriers USS Enterprise (CV-6) and USS Intrepid (CV-11) from May 1943 until he left active duty on December 2, 1945. During this time he was credited with the destruction of 12 enemy aircraft in aerial combat, plus 1 probable, between February 1944 and April 1945. LT Kirkwood was recalled to active duty on February 15, 1951, and served as an Operations and Communications Officer at NAS Niagara Falls, New York, from February 1951 to February 1954, followed by service on the staff of the Chief of Naval Air Reserve Training at NAS Glenview, Illinois, from February 1954 until he left active duty again on August 15, 1955. CDR Kirkwood remained in the Naval Reserve until his retirement on July 1, 1968.

His Navy Cross Citation reads:

For extraordinary heroism as Pilot of a Fighter Plane as Division Leader in Fighting Squadron TEN, attached to the U.S.S. INTREPID, in action against enemy Japanese forces near Okinawa on April 16, 1945. Boldly intercepting an overwhelming force of Japanese aircraft maneuvering to attack our fleet units, Lieutenant (then Lieutenant, Junior Grade) Kirkwood promptly engaged the enemy in furious combat, personally destroying four Japanese planes and directing his division in demolishing fourteen more. Quick to act when two of the hostile craft launched savage suicide dives on a surface vessel below, he immediately plunged through withering antiaircraft fire to strike smashing blows against the enemy planes and, by his relentless determination and indomitable courage, succeeded in blasting them from the sky. By his superb skill as an airman with intrepid fighting spirit and brilliant combat tactics throughout this period of intense aerial activity, Lieutenant Kirkwood contributed materially to the effective coverage provided to our surface units and reflects the highest credit upon himself and the United States Naval Service.