Ambassador Thomas Shannon has more than three decades of experience in government services and diplomacy in the US. He has served under 6 US presidents and 11 Secretaries of State. During his career, Ambassador Shannon has worked in the US Foreign Service at embassies in Guatemala, Brazil, South Africa and Venezuela.

From 2016 to 2018, he served as Under Secretary of State for Political Affairs, the third highest ranking position in the State Department. During his tenure, he was in charge of bilateral and multilateral foreign policy making and implementation. He also oversaw global diplomatic activity and US missions with international organisations.

Ambassador Shannon managed the State Department during the 2017 presidential transition, led bilateral and strategic stability talks with Russia, worked with US allies overseeing Iran’s compliance with the Joint Comprehensive Plan of Action, and expanded US engagement in Central Asia.

Holding the personal rank of Career Ambassador, he was the highest-ranking member of the United States Foreign Service, the country’s professional diplomatic corps.

Before this, he served as Counsellor to the Department, where he acted as a trouble-shooter and roving envoy for Secretary of State John Kerry. In this position, he focused on Africa, the Middle East and Southern Asia, and led US support for the UN-sponsored peace processes in Yemen and South Sudan.  

He also served as the US Ambassador to Brazil from 2010 to 2013, Special Assistant to the President and Senior Director for Western Hemisphere Affairs at the National Security Council from 2003 to 2005, Deputy Assistant Secretary of Western Hemisphere Affairs at the Department of State from 2002 to 2003, and Director of Andean Affairs from 2001 to 2002.