As the United Nations moves toward choosing its 10th Secretary-General, the history of the office offers an important warning against reducing the job to a résumé of diplomatic titles.
Since the UN’s creation, nine men have held the position. They have included politicians, career diplomats, academics, civil servants, a peacekeeping official and a former head of government. Their professional paths were markedly different, yet each brought an experience that shaped how he approached one of the world’s most difficult jobs. ht
The next Secretary-General will inherit an organisation confronting wars, geopolitical rivalry, humanitarian emergencies, climate change, financial pressures and questions about the effectiveness of multilateral institutions.
The historical record therefore provides a useful question: what did previous Secretaries-General actually bring with them when they walked into the job?
Trygve Lie: politics at the birth of the UN
Norway’s Trygve Lie, the first Secretary-General, was not a career UN official. He was a lawyer and Labour politician who had served as Norway’s justice, trade and industries, supply and shipping, and foreign minister.
His wartime experience was particularly significant. After Germany invaded Norway in 1940, Lie went to Britain and continued working with the Norwegian government in exile. He later headed Norway’s delegation to the 1945 San Francisco conference that drafted the UN Charter.
When he became Secretary-General in February 1946, he therefore arrived with political, governmental and wartime diplomatic experience — appropriate credentials for an institution being constructed in the aftermath of global war.
Hammarskjöld and U Thant: two different forms of diplomacy
Dag Hammarskjöld brought something different: technocratic independence.
The Swedish economist and civil servant became Secretary-General in 1953 and increasingly defined the office as something more than an administrative post. His tenure demonstrated how the Secretary-General could use personal diplomacy and the authority of the office to intervene in international crises.
His successor, U Thant of Burma, came from an even less conventional background. Before entering diplomacy, he had been an educator, headmaster and journalist. He was selected after Hammarskjöld was killed in a plane crash in September 1961 while on a peace mission in the Congo.
U Thant’s experience in education and Burma’s emerging diplomatic service gave him a perspective shaped by the developing world and the era of decolonisation.
Waldheim and Pérez de Cuéllar: diplomacy as a profession
Kurt Waldheim and Javier Pérez de Cuéllar represented a more traditional route to the office.
Waldheim was an Austrian diplomat and foreign minister with extensive international experience. Pérez de Cuéllar was a Peruvian lawyer and career diplomat who entered his country’s foreign service in 1940 and served in diplomatic postings including France, Britain, Bolivia and Brazil before rising to senior positions at home and at the UN.
Pérez de Cuéllar’s background is particularly revealing because he knew both sides of international diplomacy — the national foreign ministry and the UN system.
That combination would become increasingly valuable as the organisation’s peacekeeping and mediation responsibilities expanded.
Boutros-Ghali: the scholar who negotiated peace
Boutros Boutros-Ghali brought perhaps the most academically extensive background of the Secretaries-General.
An Egyptian jurist and scholar, he spent decades teaching international law and international relations before becoming a senior Egyptian diplomat and deputy prime minister for foreign affairs.
His experience was not merely theoretical. He participated in the 1978 Camp David Summit, which helped produce the 1979 Egypt-Israel peace accords, and worked extensively on international law, decolonisation, development, human rights and Middle Eastern affairs.
His career demonstrated that scholarship could complement political and diplomatic experience rather than compete with it.
Kofi Annan: the institution’s insider
Kofi Annan represented another model entirely.
Rather than arriving from national political leadership, Annan spent decades inside the UN system, including senior responsibilities in peacekeeping. He became the first person from sub-Saharan Africa to serve as Secretary-General.
His advantage was institutional knowledge: he understood the organisation’s bureaucracy, peacekeeping machinery and political culture from the inside.
That experience mattered because the Secretary-General is not only a global diplomat. The position also involves managing an enormous international institution.Ban Ki-moon: foreign policy and lived experience of war
Ban Ki-moon arrived after a 37-year career in South Korea’s foreign ministry, including postings in India, the United States and Austria and senior responsibilities involving foreign policy and national security.
His relationship with the UN dated to 1975, when he worked in South Korea’s UN division. Before becoming Secretary-General, he was foreign minister.
Ban also brought personal experience of war. He has described growing up during the Korean War and seeing the UN assist South Korea’s recovery.
That experience influenced his emphasis on peace, development and vulnerable populations, as well as his strong focus on climate change.
Guterres: the politician who became a humanitarian
António Guterres brought perhaps the most distinctive combination of recent decades: national political leadership followed by humanitarian management.
He served as Portugal’s prime minister from 1995 to 2002 and later spent a decade as UN High Commissioner for Refugees, overseeing the agency during major displacement crises including Syria, Iraq, South Sudan, Yemen and the Central African Republic.
He therefore entered the Secretary-Generalship having experienced both sides of international governance: the pressure of running a government and the consequences of government failure, war and displacement.
The common thread — and the warning
The biographies reveal a striking commonality: there has never been one standard career path to the Secretary-Generalship.
Lie brought government and wartime politics. Hammarskjöld brought independent civil-service expertise. U Thant brought education and developing-world diplomacy. Waldheim and Pérez de Cuéllar brought professional diplomacy. Boutros-Ghali combined scholarship with statecraft. Annan brought deep UN institutional knowledge. Ban brought foreign-ministry experience and multilateral diplomacy. Guterres combined political leadership with humanitarian management.
That history complicates any attempt to define a single ideal candidate.
It also exposes an important distinction: the best preparation for being Secretary-General has not necessarily been preparation for running a government. Nor has it necessarily been a career inside the UN.
The office has repeatedly rewarded a different quality — the ability to operate between governments, negotiate with competing powers, manage an international bureaucracy and use political authority without possessing the authority of a world government.
The next test
That history matters now because the UN has formally begun the selection process for the successor to Guterres. Under Article 97 of the UN Charter, the General Assembly appoints the Secretary-General following a recommendation from the Security Council.
The UN’s own description of the position captures the contradiction at the heart of the job: the Secretary-General is simultaneously diplomat and advocate, civil servant and chief executive.
The historical record suggests that the successful occupant has never been simply the person with the longest diplomatic résumé.
The harder question for 2027 is whether the next Secretary-General can combine the qualities demonstrated by the predecessors — diplomacy, independence, political experience, institutional understanding, humanitarian credibility and the ability to mediate when the major powers themselves cannot agree. In an increasingly divided international system, that may be the most important experience of all.
