Working as a seaman after completing his schooling, he returned to England soon after the First World War began and joined the British Army.

Five years later his service ended and he subsequently joined the New Zealand Permanent Air Force, the predecessor to the RNZAF.

During the early stages of the Second World War, he served in the United Kingdom at the Air Ministry before returning to New Zealand and proceeding to the South Pacific.

His father, Jesse Wallingford, was an officer in the British Army but transferred to the New Zealand Military Forces in 1911.

[1][2][3][4] In July 1916, Wallingford, by this time back in England, joined the British Army and was posted to the Artist Rifles Regiment.

[5] After 12 months, he returned to the United Kingdom and rejoined the RAF on a short service commission as a flying officer.

Wallingford flew these on a number of sorties over Samoa, seeking to identify Mau activists and dropping propaganda leaflets.

He was provided with only a flare gun, meant for use for signalling for attention in the event of a forced landing, but used this against a hostile villager throwing stones at his slow and low-flying Gipsy Moth.

[10] Later, back in New Zealand, Wallingford often flew rescue missions, looking for missing shipping and performing mercy flights.

[7] During his final months in the position by which time he held the rank of squadron leader, he was a co-author, along with Dr. Ernest Marsden, of a report for the New Zealand government on the use of radar for air defence.

In October the following year he was promoted to group captain and was sent to the headquarters of Rear Admiral John S. McCain Sr., the commander of aircraft in the South Pacific, as a liaison officer for the RNZAF.

He initially served aboard the USS Curtiss, anchored off Espiritu Santo in Vanuatu but later established a headquarters on the island itself.

[21] The RNZAF, which had grown its commitment to the military operations in the South Pacific significantly over the preceding year, established No.

Wallingford was appointed its commander and oversaw the administrative work involved in keeping the various RNZAF units running with supplies, equipment and personnel.

[1][25] He was subsequently appointed a Commander of the Order of the British Empire in "recognition of conspicuous service in operations against the Japanese".