Mark Tom Mulingbayan holds degrees of Master of Science in Environmental Engineering (2005) and Bachelor of Science in Civil Engineering (1994), both from the University of the Philippines at Diliman. He was a member of the faculty of the College of Engineering at UP, and was the Municipal Environment and Natural Resources Officer of a local government before joining the private sector. He continues to lecture on topics in environment, sanitation and sustainability for government agencies, non-government organizations and the academe. He is also one of a handful of constructed wetlands practitioners in the Philippines.
He joined the Manila Water Company in 2006 as head of its Wastewater Treatment Operations, established the Environment Department in 2009, was the Head of Sustainability from 2014 to 2017, and led the Technical Services Division of the Corporate Operations Group from 2017 to 2019. He was appointed Chief Sustainability Officer in October 2019.
He is currently a Co-Chair of the Environment and Climate Change Committee of the Philippine Chamber of Commerce and Industry.
In 2011, he was in the pioneering batch of the Water Leadership Programme at the Lee Kuan Yew School of Public Policy, National University of Singapore.