According to the enlistment record on the National Archives and Records Administration website, Walter D. Kilroy was born in 1919 in California and listed Los Angeles County as his residence. He had completed four years of college, had no dependents, and listed actor as an occupation.
On February 21, 1942 he enlisted in the Air Corps as a private and worked his way to becoming a pilot with the 501st Bomb Squadron of the 345th Bomb Group. He was one of the original cadre of pilots when the Group moved to New Guinea in 1943.
I found records of twenty-two flights piloted by Captain Kilroy from June 30 to December 22, 1943. On the last flight, he crash landed his shot up B-25 near Dumpu in the Ramu River valley and managed to walk to safety with the rest of his crew over a five day period.