美國海軍研究實驗室
Starting in 1943, after completing graduate studies, Karle worked on the Manhattan Project at the University of Chicago with his wife Dr. Isabella Karle, one of the youngest scientists and few women on the project. In 1944, they returned to the University of Michigan, where Karle worked on a project for the United States Naval Research Laboratory. In 1946, they moved to Washington, D.C. to work for the Naval Research Laboratory.