Born on May 24, 1952, Shri Mathai joined the Indian Foreign Service in 1974, after completing Post Graduate studies in Political Science at the University of Poona.

He has served in Indian Missions in Vienna, Colombo, Washington, Tehran and Brussels. As Joint Secretary (BSM) in the Ministry of External Affairs in New Delhi (January 1995 to February 1998), he headed the Division dealing with India's relations with Bangladesh, Sri Lanka, Myanmar and Maldives.

He was the Ambassador of India to Israel from February 1998 to June 2001 and to Qatar from August 2001 to July 2005. He next held the post of Deputy High Commissioner of India to the UK in London, from August 2005 to January 2007. He last served as the Ambassador of India to France (since January 2007), with concurrent accreditation to the Principality of Monaco.

Shri Mathai assumed the office of Foreign Secretary on 1 August 2011.

He is married to Smt. Gita and has two daughters.