In 1998 she completed her Master of Laws (LLM) from Yale University where her supervisor was Professor Daniel Esty.

Among other roles, she has served as a legal consultant to United Nations Framework Convention on Climate Change (UNFCCC) secretariat, as a negotiator for the Alliance of Small Island States, and as a legal adviser to the Chairs of Ad Hoc Working Groups under the UNFCCC.

She was also part of the UNFCCC core drafting and advisory team for the 2015 Paris Agreement.

[5][7] Rajamani serves as Coordinating Lead Author for the Intergovernmental Panel on Climate Change's Sixth Assessment Report.

She is a member of the influential Climate Crisis Advisory Group (CCAG), led by Sir David King, and a principal co-investigator on the inter-disciplinary Oxford University initiative, Oxford Net Zero.