Ban Ki-moon joined The Elders in June 2017 after completing his second term as UN Secretary-General in December 2016. In October 2018, he was appointed Deputy Chair together with Graça Machel.

A global advocate for climate adaptation and resilience, Ban Ki-moon has continued his work on climate change as a member of The Elders. During the Elders’ visit to Paris in 2017, he joined the delegation to meet President Emmanuel Macron for a discussion on global challenges, from climate change to conflicts, and participated in the One Planet climate summit. In 2019, Mr Ban was part of the Elders’ first official delegation to China where he met with President Xi Jinping and senior leaders to discuss global issues: from multilateralism and climate change to nuclear non-proliferation and human rights.

Ban Ki-moon is also a champion of intergenerational dialogue, gender equality and access to healthcare. In 2017, Mr Ban joined the Elders and young leaders in a symbolic “walk for peace” through central London as part of the campaign to mark The Elders’ tenth anniversary, and participated in a debate with young leaders and broadcasters.

Ban Ki-moon served as the 8th Secretary-General of the United Nations from 2007 to 2016, succeeding Kofi Annan. His first major initiative as UN Secretary-General was the 2007 Climate Change Summit, which was followed by extensive diplomatic efforts to put the issue at the top of the global agenda. In 2009, Mr Ban continued to stress his concerns for global warming at the World Climate Conference in Geneva, and in 2014 he joined demonstrators in the People's Climate March in New York City. He also called together world leaders for the 2014 UN Climate Summit, which served as a preparatory meeting for the 2015 United Nations Climate Change Conference.

Mr Ban was also a tenacious advocate for the Millennium Development Goals and their successors, the Sustainable Development Goals. He generated more than $60 billion in pledges, with a special emphasis on Africa and the new Global Strategy on Women’s and Children’s Health.

Ban Ki-moon was a strong advocate for the creation of UN Women. His advocacy for women’s rights and gender equality led him to launch the "Unite to End Violence against Women" campaign; the "Stop Rape Now" initiative; the creation of a "Network of Men Leaders"; and the establishment of a new Special Representative on Sexual Violence in Conflict. Within the UN itself, Mr Ban increased the number of women in senior management by 40%, reaching the highest level in the organisation’s history.

Furthermore, Mr Ban implemented significant UN reforms, including measures aimed at making the organisation more transparent, effective and efficient. These include heightened financial disclosure requirements, harmonisation of business practices and conditions of service and the adoption of International Public Sector Accounting Standards.

As Secretary-General, Ban Ki-moon strengthened UN peace efforts by promoting a series of steps aiming at improving the impact of the 120 000 United Nations "blue helmets" operating in the world’s conflict zones. He set up a mediation support unit, which, together with the Secretary-General’s good offices, helped to prevent, manage and resolve tensions, conflicts and crises. Particularly, he took steps to bring accountability for human rights violations through inquiries related to Gaza, Guinea, Pakistan and Sri Lanka, legal processes in Lebanon and Cambodia, and advocated the "responsibility to protect”.

Mr Ban has also sought to strengthen humanitarian response in the aftermath of the mega-disasters in Myanmar 2008, in Haiti 2010 and in Pakistan 2010, and mobilised UN support for the countries in democratic transition in North Africa and the Middle East. Mr Ban also led efforts to revive the disarmament agenda and break the deadlock at the Conference on Disarmament and urged renewed attention to nuclear safety and security in the aftermath of the tragedy at the Fukushima Daiichi Nuclear Power Plant.