5 Best UN Secretary-Generals (And Their Achievements)

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The Secretary-General is the most senior position in the United Nations. As both chief administrative officer and head of the United Nations secretariat, the Secretary-General is the top diplomat, civil servant and figure-head of the UN. It is a hugely important job, holding huge influence over global affairs and acting as a key arbitrator for global crises and conflicts.

Nine people have held the role of Secretary-General of the United Nations. All have had successes; all have had controversies. However, some have been more successful than others. So, let’s ask, who has been the best United Nations Secretary-General?

Dag Hammarskjöld

Dag Hammarskjold is often said to have been the best Secretary-General of the United Nations. From Sweden, Hammarskjold had an early career as a diplomat before becoming UN Secretary-General in 1953. Hammarskjold is renowned for his efforts to resolve many global crises during his time as head of the UN

There are many reasons why Dag Hammarskjold is often regarded as the best UN Secretary-General. Hammarskjold’s tenure as Secretary-General saw him try and improve relations between Israel and Arab states, negotiating prisoner releases between the USA and China following the Korean War and overseeing the UN’s response to the 1956 Suez Crises.

Hammarskjold’s willingness to confront global powers and attempts to address some of the most intractable crises of his time are why he is regarded as one of the best UN Secretary-Generals.

Another reason Dag Hammarskjold is seen as one of the most successful Secretary-General of the UN is his creation of the UN Emergency Force.

The UNEF was the first UN military force and was used to resolve the crises following the French, UK and Israeli invasion of Egypt in 1956. The UNEF was a fundamental change in the role of the UN and was the pre-curser to modern day UN Peacekeeping. Hammarskjold was fundamental in defining the role of forces in ending conflicts and this is a key reason he is seen as one of the best Secretary-Generals.

As UN Secretary-General, Dag Hammarskjold took an active role in resolving the conflict in the newly independent Democratic Republic of Congo (DRC). In 1960, he travelled personally to the DRC following attacks on UN forces there. Whilst traveling back from the southern Congolese region of Katanga, Hammarskjold’s plane crashed and he, along with the other 14 passengers were killed. He is the only UN Secretary-General to die whilst in office.

For his efforts to resolve the Congo crises, and the sacrifice he made, Dag Hammarskjold is again often sighted as the best Secretary-General of the United Nations.

Following his death, Dag Hammarskjold was posthumously awarded the Nobel Peace Prize. Famously, President Kennedy stated Hammarskjold was the ‘the greatest statesman of our century.”

U Thant

U Thant took the role of UN Security General following the death of Dag Hammarskjold. He is also generally considered to be one the best Secretary-Generals of the United Nations.

Thant was initially appointed acting Secretary-General to complete the remainder of Hammarskjold’s term. However, his successes in this time meant he was appointed to his own term in office. Thant was UN Secretary-General from 1961 to 1971.

As the first Secretary-General from a developing country, U Thant’s tenure as Secretary-General was important in establishing the UN as a truly global body. His representation of newly-decolonised nations is another reason he is seen as one of the important UN Secretary-Generals.

During his time at UN Secretary-General, Thant is credited with many achievements and, having overseen the United Nations during several major crises, his coordination of the international responses are still heralded to this day.

Thant’s major achievements as UN Security General include his facilitation of negotiations between the US and Soviets during the Cuban Missile Crises. His success here avoided all-out nuclear war between the super powers and is a major reason he is seen as one of the best Secretary-General of the UN.

U Thant was able to end the Congo Crises that claimed the life of Dag Hammarskjold. His success here is also a reason he is seen as one of the top UN Secretary-General

During Thant’s time as Secretary-General, two of the major world events were the Vietnam War and the ongoing Arab-Israeli conflict. Both were intractable crises without easy solutions. However, Thant is regarded as having generally upheld the UN’s position and having refrained from being seen as beholden to either side. Although he was unable to resolve either conflict, Thant’s handling of these events was seen as deft and is a further reason he is seen as one of the leading UN Secretary-Generals.

From 1967, disputes between Turkish and Greek Cypriots rose and Turkey threatened military intervention. Thant negotiated extensively on the Cyprus issue and was at that time able to prevent further military escalation. Although Turkey would later invade Cyprus in 1974, Thant’s methods of personal negotiation are seen as a model for later Secretary-General’s and another reason he is thought of as one of the best.

Ban Ki-Moon

Ban Ki-Moon was Secretary-General of the United Nations from 2007 to 2016. He is often regarded as one of the best Security Generals.

From South Korea, Ban Ki-Moon had a career as a diplomat and foreign security before becoming UN Secretary-General. Upon taking office, Ban began addressing some of the most pressing crises of the time, including the Darfur genocide, HIV/Aids pandemic and North Korea and Iran’s nuclear ambitions. His methodical attempts to address such challenges from start of his tenue mark him our as one of the strongest Secretary-General the UN has had.

Ban Ki-Moon also came into the position as UN Secretary-General at the height of the conflict following the US invasion of Iraq. Early attacks on the UN, including the August 19th 2003 bombing of the UN headquarters in Baghdad which killed the UN Special Representative to Iraq Sergio Vieira de Mello, had made the conflict a difficult situation for the United Nations. Ban was seen as deft at navigating the politics of the UN and its role in Iraq and this is another important reason he is seen as one of the best UN Secretary-Generals.

Throughout his time as Secretary-General, Ban Ki-Moon was a strong advocate for action on climate change. From early in his posting, he adopted it as one of his key messages and this marks him out as one of the most important Secretary-Generals.

Another important issue highlighted by Ban Ki-Moon as Secretary-General was LGBT rights. In 2012 he delivered a speech called ‘’The Time Has Come” which called on the United Nations to do more to promote the rights of sexual minorities. This departure from the status-quo in favour of a marginalised group is further reason Ban Ki-Moon can be seen as the best UN Secretary-General.

By the end of his time as Secretary-General, the conflict between Russia and Ukraine had been ongoing for two years. As a new Cold War became the geo-political reality, Ban Ki-Moon strongly called out Russian aggression. A controversial, but important, move, it can be seen as another reason for the high regard that is given to Ban Ki-Moon for his time as UN Secretary-General.

United Nations Online Courses

If you want to learn more about the United Nations, and some of the major successes it has had, we highly recommend the online course Global Diplomacy: The United Nations in the World offered by SOAS in London. We think it provides one of the best overviews of the UN and its role in the current global order. SOAS is also one of the top universities in the world for international relations and courses related to the UN.

The Sustainable Development Goals (SDG) underpin all of the UN’s work. In order to fully understand the United Nations, and what it does, you need a basic understanding of the SDG. We think the online short course The Sustainable Development Goals – A Global, Transdisciplinary Vision For The Future offered by the University of Copenhagen is one of the best introductions to the SDG.

The University of Leiden in the Netherlands offers an online short course on The Changing Global Order. It includes a specific look at how shifting international power dynamics are affecting the current global system and the United Nations. For those wanting to understand the challenges the UN faces, this online course is a must.

Kofi Annan

Kofi Annan was Secretary-General of the United Nations from 1997 to 2006. The first Secretary-General from Africa, Kofi Annan is regularly heralded as one of the most successful Security Generals to lead the UN.

Following a long and distinguished career within the UN, Kofi Annan became Secretary-General following the tenue of Boutros Boutros-Ghali.

Annan achieved much during with time as Secretary-General. Major achievements include progress on HIV/Aids, especially in Africa and the proliferation of chemical and nuclear weapons, as well as his work on human rights, labour, the environment and anti-corruption. Key successes such as these during his time mark him out as one of the best UN security General’s.

Another reason Kofi Annan is often said to be the best UN Secretary-General is the establishment of the Millennium Development Goals. These marked out eight key areas of global development that should be focused on over the next fifteen years.  191 UN member states and 22 international organisations signed-up to the Millennium Development Goals and they are seen as one of the most important drivers of international development and a major achievement by Annan.

During his time as UN Secretary-General, Kofi Annan addressed many global challenges. He was instrumental in defining the role of the UN immediately following the attacks of 9/11. He was also in charge during the US invasions of Iraq and Afghanistan and navigated the international political fall-out of both.

Kofi Annan made significant efforts to reform the United Nations during his time as Secretary-General. He was instrumental in reforming the UN’s efforts in peacekeeping and peace building. He also called for the complete overhaul of the United Nations Secretariat. Although not all his reforms were seen through, his concerted efforts to modernise and improve the United Nations marks him out as one of the most important Secretary-Generals.

As a mark of his success, Kofi Annan was awarded the Nobel Peace Prize, alongside the United Nations as a whole, in 2001. The award was given in recognition of Annan’s ‘’work for a better organized and more peaceful world’’. As only the second Secretary-General to be awarded the Nobel Peace Prize, this is another factor in establishing Kofi Annan as one of the top people to lead the UN.

Gladwyn Jebb

A final candidate for best UN Secretary-General could be Gladwyn Jebb. He was a British civil servant who acted as the first Secretary-General of the United Nations from 1945 – 46. He held the position following the establishment of the UN and was custodian of the role until the first full Secretary-General could be selected.

Acting as Secretary-General during the crucial first days of the UN, Gladwyn Jebb was instrumental in establishing the role of Secretary-General and ensuring its impartiality and independence.

Gladwyn Jebb oversaw the appointment of the first full UN Secretary-General – Trygve Lie. Negotiations between world powers, especially the US and Soviet Union complicated the establishment of the United Nations and made appointing the role of Secretary-General a challenge. Although Jebb held the position for only a short-time, his role in ensuring a smooth transition to a permanent Secretary-General marks him out as one of the best.

At the end of World War Two, the victorious powers turned their attention to creating a world system where future global conflicts would be avoided. The establishment of the UN was a key part of this. As the first person to hold the role of Secretary-General, Gladwyn Jebb played a vital role in creating the UN in the first complex and chaotic days after the war. For this, he should be regarded as one of the best Secretary-Generals.

Interestingly, Gladwyn Jebb is the only UN Secretary-General to come from a permanent member state of the UN security council.

If you want to learn more about the United Nations, and the successes it has had, explore our page on the top UN online courses here.


Duncan is the founder of Humanitarian Careers. With over ten years experience in the aid industry across fifteen countries, Duncan set-up Humanitarian Careers to help people launch their own career in international aid.