It is likely that his friendships with then-Secretary of State Cordell Hull and Senator Kenneth McKellar, both Tennesseans, played a role in his appointment.

During that time, Hawaii was governed by Army generals Walter Short, Delos Emmons, and Robert C. Richardson, Jr. A conservative Democrat, Stainback, whose full powers were restored on April 13, 1944, played a significant role in the lifting of martial law in wartime Hawaii.

Upon resigning his post on May 8, 1951, Stainback had served eight years, eight months and six days, the longest of any appointed governor up to that point.

[7]: 125–126 By the middle of the year, statehood campaigners had become openly critical of Stainback because of his seemingly ambivalent attitude to pursuing the issue.

[4]: 44  Stainback argued for Commonwealth status similar to Puerto Rico instead of statehood,[4]: 44  suggesting that Hawaii would benefit from the federal tax exemption which would stimulate economic growth.

[dead link‍][9] His son, Macklin Fleming, was an associate justice of the California Court of Appeal and an early opponent of affirmative action.