He is survived by wife Gurcharan Singh and three daughters.
Here is the timeline of his five-decade old career in bureaucracy and politics.
1982-1985: Governor of the Reserve Bank of India
1985-87: Served as Deputy Chairman of Planning Commission
1987-90: Secretary General of South Commission in Geneva
1990: Appointed Advisor to Prime Minister on Economic Affairs March
1991: Appointed chairman of University Grants Commission
1991: Elected to Rajya Sabha from Assam, and re-elected in 1995, 2001, 2007 and 2013
1991-96: Finance Minister under P V Narasimha Rao government
1998-2004: Leader of the Opposition in Rajya Sabha
2004-2014: Prime Minister of India
Singh, who was finance minister under the then prime minister P V Narasimha Rao, was the architect and the brainchild of economic reforms in 1991 that pulled India from the brink of bankruptcy and ushered in an era of economic liberalisation that is widely believed to have changed the course of India's economic trajectory.