Jaishankar was born on 9 January 1955 in New Delhi, India to prominent Indian strategic affairs analyst, commentator, and civil servant K. Subrahmanyam and Sulochana. He is the brother of historian Sanjay Subrahmanyam and S Vijay Kumar, former Rural Development Secretary of India. He is married to Kyoko, and has two sons and a daughter.
He did his schooling from Air Force Central School, New Delhi and is a graduate of St Stephen’s College at the University of Delhi. He has an MA in Political Science and an MPhil. and PhD in International Relations from Jawaharlal Nehru University (JNU), where he specialised in nuclear diplomacy.
Joining the Indian Foreign Service in 1977, Jaishankar served as third secretary and second secretary in the Indian mission to the Soviet Union in Moscow from 1979 to 1981, where he studied Russian. He returned to New Delhi, where he worked as a special assistant to the diplomat G. Parthasarathi and as under secretary in the America’s division of India's Ministry of External Affairs, dealing with the United States. He was part of the team that resolved the dispute over the supply of US nuclear fuel to the Tarapur Power Stations in India. From 1985 to 1988 he was first secretary at the Indian embassy in Washington D.C.
From 1988 to 1990, he served in Sri Lanka as First Secretary and political adviser to the Indian Peacekeeping Force (IPKF). From 1990 to 1993, he was Counsellor (Commercial) at the Indian mission in Budapest. Returning to New Delhi, he served as Director (East Europe) in the Ministry of External Affairs and as press secretary and speechwriter for President of India Shankar Dayal Sharma.
Jaishankar was then Deputy Chief of Mission at the Indian Embassy in Tokyo from 1996 to 2000. This period saw a downturn in Indo-Japan relations following India's Pokhran-II nuclear tests as well as a recovery after a visit to India by then Japanese Prime Minister Yoshiro Mori. Jaishankar is reported to have helped introduce future Japanese Prime Minister Shinzō Abe to his Indian counterpart, Manmohan Singh. In 2000, he was appointed India’s ambassador to the Czech Republic.