He served in that position from 1934 up to the time of the Japanese invasion in 1942. (In this period, the northern part of what is now Papua New Guinea, including New Britain and Bougainville, was administered by Australia under a League of Nations mandate; the southern part, Papua, was an Australian colony.) The manifold responsibilities of Administrator ranged from education and justice to defence, with often conflicting advice or direction coming from the Permanent Mandates Commission and the Australian government and pressures as well from the various religious missions and commercial mining and plantation interests—the latter nearly the sole source of the Territory's revenues. Keenly interested in exploration, he led an expedition to the upper Sepik in 1935 (the party included the young J.K. McCarthy) and subsequently sponsored the Hagen-Sepik Patrol (1938–39) which explored the last great unknown tract of the Territory. He was knighted for his work organising relief efforts after the 1937 volcanic eruption that nearly destroyed the territory's capital, Rabaul.