He studied mechanical engineering at the Indian Institute of Technology Madras but left after a semester. He subsequently studied economics and philosophy at Princeton University but left and returned to India where he received a law degree from Allahabad University.
In his career of 30 years, he has worked on around 500 Public Interest Litigations. His first important case was the 'Doon valley case' where the illegal mining was creating an environment hazard. He then filed a PIL in the Bhopal gas tragedy and the Narmada case also. He also investigated the 'bofors case'. He was the Delhi president of the people's Union for Civil Liberties, a human rights organization. He is a strong supporter of clean Judiciary.
He along with Arvind Kejriwal, is involved in the Anna Hazare-led anti corruption movement in India. He was a member of the joint committee constituted in April 2011 by India to draft the Lokpal Bill. He along with other members of Team Anna clashed with government ministers on the bill. He described the Lokpal Bill introduced in parliament as a corruption bill because it contained harsh punishment for whistle-blowers and protected the corrupt. Indian parliament issued him a notice of breach of privilege for his remarks against the Parliament and parliamentarians which he denied. He speaks in a frank and clear manner on matters of state and justice that have been made acutely apparent in this struggle for recognition and justice.
Prashant has written many books on judiciary and the cases he fought. Some of them are listed below:
a. Appointment of Thomas as CVC Chief.
b. The Doon Valley case.
c. Bhopal Tragedy case.
d. Narmada case.
e. Important cases litigation.
f. 2G scam by A. Raja and team.