O'Malley had a particular interest in the management and protection of the fishery and fur seal resources of the Territory of Alaska. Thanks in part to his advocacy and despite numerous obstacles to its passage, the United States Congress passed the so-called "White Law" of June 6, 1924, which gave the United States Secretary of Commerce, to whom the Commissioner of Fish and Fisheries reported, broad regulatory powers over fisheries in Alaska. For the rest of his tenure as commissioner, O'Malley annually spent the entire fishing season in Alaska to oversee personally the implementation of BOF regulations and policies authorized by the law. This played an important role in the rehabilitation of what had been badly depleted salmon runs and other fisheries in Alaskan waters and establishing their future sustainability.
