After attending Hillsboro High School,[3] he was appointed to the United States Naval Academy in Annapolis, Maryland, graduating with the Class of 1918 in 1917.

[3] In 1923, he helped perform the first tests of Carl Norden's prototype bombsight[1] at the Naval Proving Ground in Dahlgren, Virginia.

[3] After the United States entered World War II, Ballentine served as the second commanding officer of the escort carrier USS Long Island from 26 December 1941 to 18 April 1942.

[8] Ballentine served as chief of staff to Task Group 34.2 commander Rear Admiral Ernest D. McWhorter aboard USS Ranger during the Allied invasion of French North Africa in November 1942.

[10] Promoted to rear admiral, Ballentine next served as chief of staff for Naval Air Force Pacific.

Based aboard USS Bon Homme Richard operating near Japan as part of Task Force 38, Ballentine continued in this role until 19 August 1945.