Medha Patkar was born in Mumbai, Maharashtra, to Indumati and Vasant Khanolkar, a freedom fighter and labour union leader, on 1 December 1954. Patkar earned an MA in Social Work from Tata Institute of Social Sciences. She worked with voluntary organisations in Mumbai's slums for 5 years and tribal districts of North-East districts of Gujarat for 3 years. She worked as a member of faculty at Tata Institute of Social Sciences but left her position to take up the field work. She was a PhD scholar at TISS, studying Economics development and its impact on traditional societies.After working up to M.Phil level she left her unfinished PhD when she became immersed in her work with the tribal and Peasant communities in the Narmada valley spread over three states.

Narmada Bachao Andolan (NBA) is a social movement which began in 1985 consisting of adivasis, farmers, fish workers, labourers and others in the Narmada valley along with the intellectuals including environmentalists, human rights Activists, Scientists, academicians, artists who stand for just and sustainable development. Sardar Sarovar Dam in Gujarat is one of the biggest dams on Narmada where the non-violent people's struggle has questioned social and environmental costs, undemocratic planning and unjust distribution of benefits. The struggle is still on in the Sardar Sarovar affeced areas and also other large and medium dams on Narmada and its tributaries. It has led to thousands of project affected families receiving land based rehabilitation and continues to fight against submergence and displacement without rehabilitation of more than 40,000 families residing in these submergence area of Sardar Sarovar till date. Many of its claims and critique on economic, social and environmental aspects of Sardar Sarovar and Narmada valley development project stand vindicated today. Patkar has also questioned the wisdom of the currently popular developmental strategy of linking rivers in India as a means to address issues of water shortage.

Medha Patkar along with other Activists registered PIL in the High Court of Mumbai, alleging violations by property tycoon Niranjan Hiranandani in building luxury flats instead of affordable houses. Hiranandani had signed a lease for the 230 acres of land in 1986 at rate of Re 1 per hectare in a tripartite agreement with the state and Mumbai Metropolitan Region Development Authority. Responding to PIL Maharashtra High Court judges says that" we appreciate the elegance of the construction and the intent on creating an architecture marvel for the city of Mumbai, we see the specific intent of wholly ignoring the most vital, and perhaps the only, condition in tripartite agreement (to create affordable houses of 40 and 80 sq m)". If calculated according to the current market price, the quantum of the scam will be around Rs. 450 billion. The judgement of 2012 directed Hirandani to build 3,144 houses for the low income groups before any other construction at Hirandani gardens which is yet to happen. The case is at the stage of final hearing at HC of Mumbai.

NBA has been running JEEVANSHALAS- schools of life, since 1992 with about 5,000 students having passed out and many graduated. Tens of them are under training in athletics and some have won many awards. NBA also successfully established and managed two micro hydral projects which got submerged due to SS dam. It has been working in many sectors over last 30 years including health, employment guarantee, Right to Food and PDS, rehabilitation and environment protection.

It is a struggle for housing rights in Mumbai, started in 2005 and continues to fight for rights of slum-dwellers and those cheated by the builders in various rehabilitation and re-development projects. It all began when the government of Maharashtra demolished 75,000 houses of the poor in 2005, against its own promises before election. strong people's movement was founded by Medha Patkar and others when she gave the slogan in a large public meeting at Azaad Maidaan Mumbai. It was through mass action that the communities were re-built on the same sites and continue to assert and attain their right to shelter, water, electricity, sanitation and livelihood. As members of working class GBGBA respects the slum-dwellers for contribution to the life of the city and involves them in equitable and inclusive planning for urban development.

Tata Motors started constructing a factory to manufacture their $2,500 car, the Tata Nano at Singur. She protested against the setting up of the plant at Singur, West Bengal. Patkar's convoy was assaulted, allegedly by CPI(M) Activists, at Kapaseberia in East Midnapore district while on her way to strife-torn Nandigram. At the height of the agitation, Ratan Tata had made remarks questioning the source of funds of the agitators. In October 2008 Tata announced that the factory would not be completed and that the production of the Nano will be set up in Sanand, Gujarat.

A demolition took place on 2 and 3 April 2013 in the Golibar area, Mumbai, Maharashtra evicting 43 houses and displacing more than 200 people. the whole project is to displace thousands of families and 50–100 years old communities that are demanding in-situ and participatory housing rights. Medha Patkar with more than 500 slum dwellers set on indefinite fast to protest against any further demolition until the inquiry into the matter is completed. Patkar has alleged corruption and "atrocities" by builders in the city's slum rehabilitation scheme, and called for the halting of six projects by the Slum Rehabilitation Authority, until a proper inquiry is conducted. The inquiry was conducted giving partial solutions hence communities continue with their struggle.

In January 2014, Medha Patkar joined the Aam Aadmi Party, a political party led by Arvind Kejriwal. She and her organisation, National Alliance of People's Movement, provided support to the Aam Aadmi Party during the Lok Sabha campaign.

Patkar also contested 2014 Lok Sabha election from the North East Mumbai constituency as an Aam Aadmi Party candidate. She lost, receiving 8.9% of the vote cast in North East Mumbai constituency, trailing at third position behind Kirit Somaiya (BJP candidate, winner) and Sanjay Patil (NCP candidate). She resigned from Aam Admi Party's primary membership on 28 March 2015.