Maria Socorro began her career at SyCip Salazar, Hernandez & Gatmaitan, one of the top law firms in the Philippines. After deciding to devote her legal skills to the cause of the environment, she joined the Philippine Department of Environment and Natural Resources. At DENR, she worked on the development and implementation of laws and regulations on pollution and environmental impact assessment and represented her country in negotiations on the Kyoto Protocol. In 2001 she moved to the Environmental Law Center of the International Union for Conservation in Bonn where she provided legal advice to negotiators from developing countries on land use, land-use change and forestry. From 2006 to 2016 she was with the secretariat of the United Nations Framework Convention on Climate Change where she served as Secretary to the Compliance Committee of the Kyoto Protocol and was part of the secretariat's legal and advisory team for the Paris Agreement. She relocated to Nairobi in 2016 to head the National Environmental Law Unit of UNEP's Law Division, leading the Unit's work on technical legal assistance to countries, while continuing to provide advice to intergovernmental processes such the UNFCCC and the United Nations Convention to Combat Desertification.
She has a degree in Economics (Honors Programme) and a Juris Doctor degree from the Ateneo de Manila University. She obtained her Master of Laws degree from Harvard Law School. She is a member of the Philippine and New York Bar.