Sprague was born in Dorchester, Massachusetts, and attended the Boston Latin School, and the United States Naval Academy in June 1914 where he was given the nickname “Ziggy”. Due to the American involvement in World War I he received his commission as an Ensign one year early on June 28, 1917, finishing forty-third out of 199.
From March 1922 to November 1923, Sprague was assigned to Aircraft Squadron VS-1 with the Atlantic Fleet based on the seaplane tender USS Wright (AV-1). He reported to his next duty station Naval Air Station, Anacostia, near Washington, DC, in November 1923 where he served as a Test Pilot, Operations Officer, and Executive Officer. As a Test Pilot he conducted experimental and research work at the Naval Aircraft Factory in Philadelphia, Pennsylvania in 1923, where he contributed to the development of aircraft carrier catapult systems. From March 1926 to February 1928 he assisted inventor Carl Norden in the laboratory and as a Test Pilot at Naval Air Station Hampton Roads, Virginia with improvements to the Mark-1 aircraft carrier arresting gear system for USS Lexington (CV-2) and USS Saratoga (CV-3).
Sprague reported to USS Lexington (CV-2) in March 1928 where he assumed the duties of Flight Deck Officer and Assistant Air Officer. In January 1929 Lexington along with USS Langley (CV-1) and USS Saratoga (CV-3) participated in Fleet Exercise IX, a simulated aerial attack on the Panama Canal. Sprague’s tour on Lexington ended in April 1929. Returning to the U.S. Naval Academy in May 1929 Sprague served as Executive Officer of VN-8-D5. On June 10, 1930 he was promoted to Lieutenant Commander. His tour at the Naval Academy ended in November 1931.
Sprague served as Squadron Commander of VP-8 in Panama in December 1931 to April 1934. The squadron was based on the seaplane tender USS Wright (AV-1) homeported at the Norfolk Navy Yard. In 1933 the squadron was moved to Hawaii where Sprague became the first Navy Pilot to fly a thirteen-hour round-trip from Hawaii to Midway Island in February 1934. From May 1934 to July 1936, Sprague served as Air Operations Officer at Naval Air Station, Norfolk, Virginia where his department serviced several aircraft carrier squadrons.
In July 1936, Sprague was assigned to the newly constructed aircraft carrier USS Yorktown (CV-5) as Air Officer. After her commissioning, he piloted the first two landings ever made on Yorktown. In addition, he was the first pilot to test the catapult system on Yorktown. Sprague was promoted to Commander in December 1937. He spent all of 1938 managing the Air Department and aircraft squadrons on Yorktown. In February 1939 Yorktown participated in Fleet Problem XX in the Caribbean. Shortly thereafter Sprague left the carrier in June 1939. Sprague was ordered to the Naval War College in Newport, Rhode Island in June 1939 where he spent 3 months in study before reporting to his first sea command, the 21-year old oil tanker USS Patoka (AO-9) at Puget Sound Naval Shipyard, Bremerton, Washington. Sprague commanded Patoka until June 1940 when he was sent back to the Naval War College for two more months of study.
Sprague was assigned as Air Officer of Gulf Sea Frontier, Miami, Florida in June 1942. His duties involved improving defenses, keeping the sea lanes open, and countering the German U-boats on the Southeast coast of the United States. Upon achieving his goals he was transferred in March 1943. In April 1943, Sprague was transferred to Naval Air Center, Seattle, Washington where he served as Commander of the base and nearby Naval Air Station, Sand Point. This duty ended abruptly when he was assigned as the Commanding Officer of the newly constructed fast fleet carrier USS Wasp (CV-18) in October 1943.
Arriving at Bethlehem Steel Company Fore River Yard near Boston, Massachusetts, Sprague took command of Wasp (CV-18) where she was commissioned on November 24, 1943. The carrier was quickly sent to the Pacific where she joined the war against the Japanese. Her first combat missions were to destroy enemy aircraft, installations, and surface craft on Marcus and Wake Islands in May 1944. In June 1944 Wasp participated in the invasion of Saipan and the Battle of the Philippine Sea. On July 9, 1944, shortly before leaving Wasp, Sprague was promoted to Rear Admiral at age 48.
Sprague was designated as Commander Carrier Division 25 on July 23, 1944 with his flag in USS Fanshaw Bay (CVE-70). In September 1944 his Task Unit supported the Morotia landing.
Sprague’s greatest achievement came on October 25, 1944 when his Task Unit 77.4.3 (Taffy III) consisting of 6 escort carriers, 3 destroyers, and 4 destroyer escorts fought off the vastly superior Japanese Centre Force at the Battle off Samar. The Japanese force consisted of 4 battleships, 6 heavy cruisers, 2 light cruisers, and 11 destroyers off the Island of Samar in the Philippines. The Taffy CVE pilots bombed, strafed, and made dry runs on the battleships and cruisers of Center Force. For the leadership he displayed in this incident, he received the Navy Cross.
On February 19, 1945, Sprague assumed command of Carrier Division 26 embarked on USS Natoma Bay (CVE-62) for the invasion of Iwo Jima where his unit provided close air support for the Marines ashore. The next month he moved his flag back to USS Fanshaw Bay (CVE-70) for the invasion of Okinawa. In April 1945, Sprague was given command of Carrier Division 2, a fast carrier Task Group and moved his flag to USS Ticonderoga (CV-14) on June 1, 1945. His Task Group operated against the Japanese home islands of Kyūshū, Honshū, and Hokkaidō. Sprague received the notification of the end of hostilities while steaming 151 miles off the eastern coast of Honshū on August 15, 1945. Four days after the Japanese surrender, Sprague and USS Ticonderoga (CV-14) entered Tokyo Bay.
At Corpus Christi, Texas Sprague was assigned as Chief of Naval Air Basic Training in August 1946. In January 1948 he was redesignated as Commander, Naval Air Advanced Training. His tour ended in April 1948. Sprague’s last seagoing command was as Commander, Carrier Division 6 with his flag in USS Kearsarge (CV-33) from May to October 1948. During this tour Kearsarge operated in the Mediterranean. On January 1, 1949 to February 1950, Sprague was Commander of Naval Air Bases, Eleventh and Twelfth Naval District at Naval Air Station Coronado in San Diego, California. Reassigned in March 1950, Sprague was moved to Alaska where he served as Commandant, Seventeenth Naval District and Commander, Alaskan Sea Frontier on Kodiak Island. It was from here that he embarked on a B-29 and became the first U.S. Navy admiral to fly over the North Pole on November 12, 1950.