Hyland was born in 1912 in Philadelphia, the son of a naval officer. He graduated from the U.S. Naval Academy in 1934 and completed naval aviation training in 1937. Posted to the Philippines, he was located there when the Japanese attacked Pearl Harbor to begin US involvement in World War II. He participated in the defense of the Philippines, and the subsequent Allied withdrawal to Australia, winning the Distinguished Flying Cross for rescuing a British airman in the Molucca Sea.^[2] He then became the personal pilot of Admiral Ernest King, then Chief of Naval Operations. Upon returning to the Pacific Theater in 1943, he took command of an air squadron based on USS Intrepid. He participated in numerous operations, earning a Silver Star for leading a ground attack against the Japanese at Kure on March 19, 1945, and another Distinguished Flying Cross and the Air Medal for other missions against the Japanese.^[2]

After the war, he served stints as a test pilot, then took command of the carrier USS Saratoga in 1958.^[3] He later commanded Carrier Division Four, then moved to a staff position at the Strategic Plans Division in Washington DC. In 1965, President Lyndon Johnson selected him ahead of 72 more senior rear admirals for promotion and command of the US Seventh Fleet, then operating off Vietnam and heavily involved in US operations there.^[2] Hyland commanded the fleet for nearly two years before being promoted again and taking command of the entire Pacific Fleet in 1967, a four star billet. He played a central role, not only in ongoing operations in Vietnam, but also in two major incidents during this time: the fallout of the capture of USS Pueblo by North Korea, and the fatal accident and fire on USS Enterprise.^[2]

Admiral Hyland retired on January 1, 1971. In retirement, he maintained an interest in naval aviation, served in business directorships, and settled in Honolulu.^[1] He was married to the former Florence Day Whiting, who died in 1991; they had four children: sons John J. Hyland III and Whiting Walker Hyland and daughters Nancy Arnold and Pamela Hyland.

A non-exhaustive list of military awards is as follows:

Admiral Hyland was also granted the John Paul Jones Award for leadership by the Navy League in 1966.

• Citations for Admiral Hyland's awards from the Military Times