He chaired the Chiefs of Staff and was a major decision - maker during the war .
Leahy was recalled to active duty as the personal Chief of Staff to President Franklin D. Roosevelt in 1942 and served in that position throughout World War II .
Leahy chaired the Chiefs of Staff and was a major decision - maker during the war .
Leahy was recalled to active duty as the personal Chief of Staff to President Franklin D. Roosevelt in 1942 and served in that position throughout World War II .