After military service in 1939-43, he joined the International Committee of the Red Cross (ICRC) and traveled across wartime Europe, negotiating prisoner-of-war exchanges and food relief assistance.
When oil prices quadrupled at the end of 1973—a consequence of actions by the Organization of the Petroleum Exporting Countries—the twin shocks of recession and inflation rippled through the world economy.
Yet Long managed to hold the world's democratic industrial governments, as well as some 20 developing countries, to the free trade commitments they had made at the start of negotiations.
Not only did many tariffs drop, the Tokyo Round also represented the most comprehensive effort until then to eliminate or control other sorts of trade barriers, like quotas and export subsidies.
Because of his close personal ties with many leading French politicians, Oliver Long became an intermediary between Charles de Gaulle's government in Paris and the Algerian National Liberation Front.