Till his election to Rajya Sabha from Karnataka in July 2016, his permanent residence was at Khairatabad, Hyderabad, Telangana.

When Ramesh was 17, in 1971, he read Asian Drama, one of the early books of Gunnar Myrdal and wrote to him at the Stockholm International Peace Research Institute.

He returned to India in December 1979 and worked as assistant to economist Lovraj Kumar at the Bureau of Industrial Costs and Prices.

He then worked in the Planning Commission (advisor to Abid Hussain), Ministry of Industry and other economic departments of the Central Government, including: analysing energy policy during 1983–85, reorganising the CSIR in 1986 and implementing technology missions during 1987–89.

The central government invited him to join the official delegation to the World Trade Organization meeting in Seattle in 1999.

[14] From 2000 to 2002, Jairam served as deputy chairman, State Planning Board, Government of Karnataka and on the Economic Advisory Council of Andhra Pradesh.

[5] Jairam also served as Secretary in the All India Congress Committee, Deputy Chairman of the Karnataka Planning Board (2000–2002), member of the Rajasthan Development Council (1999–2003), and Economic Advisor to the government of the state of Chhattisgarh (2001–03).

Following his 2009 re-election to the Indian Parliament, on 28 May 2009 Jairam was given independent charge of Environment and Forests as Minister of State in the Congress-led administration.

He was chief negotiator for India at the 2009 United Nations Climate Change Conference held in Copenhagen, Denmark, between 7 and 18 December 2009.

[5][17] Jairam has accepted the offer to serve as a member of the International Advisory Board (IAB) which gives strategic policy advice to the executive director of United Nations Environment Programme (UNEP) on the programmatic direction of International Environmental Technology Centre (IETC).

[19] Jairam Ramesh became a Member of Parliament, Rajya Sabha on a ticket from Indian National Congress Party.

[20] During his tenure, he falsely accused the villagers of Pithampur in Madhya Pradesh of secretly smuggling out toxic waste from Carbide factory and dumping it.

[21] On 19 December 2020, Jairam tendered apology to Vivek Doval and his family in regard to defamation case filed by latter, after Jairam accused Vivek Doval of dealing with black money syndicate as per an article published in The Caravan under the title of The D Companies.