Extremely strong-willed and effective, he personally led direct and practical diplomatic initiatives. From historical perspective, he is considered the best UN Secretary-General to date. He opposed the imperialist designs of communism and supported decolonisation.

He was the youngest son of the Prime Minister of Sweden in the years 1914–17 who served also as a member of the Permanent Court of Arbitration, Chairman of the Nobel Foundation and Governor of Uppland. He distinguished himself at the University of Uppsala, where he studied literature and history, among other subjects. He mastered English, French and German, and achieved stylistic finesse in Swedish. His main field of intellectual and professional interests was political economy, but he devoted his life to public service.

He is considered the author of the term “planned economy” which he is said to have coined while serving as the secretary of the Riksbank (the central bank of Sweden). Together with his eldest brother Bo, the then Undersecretary at the Ministry of Social Affairs, he established the foundations for the later development of the so-called welfare state. He attracted public attention as an international financial negotiator during the talks on post-war economic reconstruction of Europe, the discussions related to the Marshall Plan and his work as the head of the executive committee of the OEEC (the predecessor of the OECD). As a financial advisor to the Swedish Ministry of Foreign Affairs and the Vice Minister of Foreign Affairs (1951), he consistently implemented his policy of international economic co-operation. He managed to preserve military neutrality of Sweden.

Elected Secretary-General of the United Nations in 1953 by an almost unanimous vote, he was re-elected four years later. He personally negotiated the release of American POWs after the Korean War. He tried to employ “preventive diplomacy” and to win greater independence and effectiveness for the post of Secretary-General of the United Nations. He initiated (in 1958) the campaign of sending UN observers to conflict-stricken countries; he secured the withdrawal of American and British troops from Liban and Jordan. Thanks to those initiatives, the United Nations developed procedures and tactics for future activities.

Hammarskjoeld dealt with the problems of former colonies which had just acquired independence. In 1960, after the withdrawal of Belgians from Congo, the new government, faced with the mutiny in its own army, the secession of the natural resources-rich Katanga province and the intervention of Belgian troops, asked the United Nations for help and the UN responded by sending peace troops to the country. The following year, armed conflict broke out between Katanga and Congo forces. Hammarskjoeld set off on a face-to-face meeting with Moise Tshombe, president of the Katanga State. While on route, the plane carrying the Secretary-General and 15 other persons crashed close to the border with Northern Rhodesia (today’s Zambia). Last year, at the initiative of famous lawyers, the investigation into Hammarskjoeld’s death was resumed as a result of new evidence which suggest that the plane was shot down.