Belonging to the 1963 batch of the Indian Foreign Service, Amb. Mansingh is considered one of the most distinguished Indian diplomats in history. He has the unique distinction of having served as the Foreign Secretary in the Ministry of External Affairs as well as the High Commissioner of India to the UK and the Ambassador of India to USA. He has also served as the High Commissioner of India to Nigeria. Earlier, he has served as the Joint Secretary (Estt), Director General of the ICCR and Dean of the Foreign Service Institute of the MEA. Since his retirement from the active service, he has been sharing his experiences with the Foreign Service Institute as the Honorary Professor Emeritus and also with various foreign Institutes, including the Brookings Institution in the US.
Other positions Amb. Mansingh has held include: President of the Forum for Strategic Initiatives based in New Delhi, member of International Advisory Council, APCO International based in Washington, member of Governing Body of Development Alternatives based in New Delhi, and Global Envoy for Buddhism of International Buddhist Confederation based in New Delhi.