The United States entered World War II as a result of the Japanese attack on Pearl Harbor on 7 December 1941, and Nygren enlisted in the United States Naval Reserve in 1942 at the age of 17 [REF].
Nygren served as damage control officer aboard the destroyer in 1946 as she was prepared for use as a target in the Operation Crossroads atomic bomb tests at Bikini Atoll later that year.