Prior to becoming Governor of Arunachal Pradesh, he was secretary-general of a think tank in Delhi, the University of Pennsylvania Institute for the Advanced Study of India.

[7] In addition, he worked hard for ensuring connectivity of Arunachal Pradesh with the rest of India by building an airport in the state, constructing a railway line and improving the road network.

From 1956 to 1959, he was Third Secretary in Iran and concurrently attended the Tehran University to study the Persian language.

Singh has been a member of 19 Indian delegations to the UN General Assembly and the United Nations Commission on Human Rights.

Singh was a frequent writer and commentator on international relations, geopolitics and current developments.

[10] He died at Sir Ganga Ram Hospital in Delhi on 1 December 2009, aged 77, after a brief illness.