Borgnine joined the United States Navy in 1935, after graduation from James Hillhouse High School in New Haven, Connecticut. He was discharged in 1941, re-enlisted when the United States entered World War II, and served until 1945 (a total of ten years), reaching the rate of gunner's mate 1st class. He served aboard the destroyer USS Lamberton. His military decorations include the Navy Good Conduct Medal,American Defense Service Medal with Fleet Clasp, American Campaign Medal, Asiatic-Pacific Campaign Medal and the World War II Victory Medal.
Borgnine received the honorary rating of chief petty officer in October 2004 from Master Chief Petty Officer of the Navy Terry D. Scott for Borgnine's support of the Navy and naval families worldwide.