Eddleman went to Australia with General Walter Krueger in early 1943 as Assistant Chief of Staff, G-3, and remained there until 1945. He participated in all of Sixth United States Army's campaigns, including the occupation of Japan. He was awarded the Army Distinguished Service Medal for his activities in the Leyte and Luzon Campaigns, and the Silver Star for reconnaissance under fire at Biak, Leyte, and Manila. He was promoted to Brigadier General at the Leyte beachhead.