James Thornton is the CEO of ClientEarth. In January 2009 he was selected by the New Statesman as one of 10 people who could change the world.

He is an environmental lawyer and social entrepreneur. A member of the bars of New York, California and the Supreme Court of the United States, and a solicitor of England and Wales, he moved from Wall Street law practice to found the Citizens' Enforcement Project at NRDC in New York, where he brought some 80 federal lawsuits against corporations to enforce the Clean Water Act when the Reagan Administration stopped enforcing the law. He won these cases and embarrassed the government to start enforcing the law again. 

He moved to Los Angeles and founded the Los Angeles Office of NRDC, which does internationally important environmental work with the support of the Hollywood community. He was Editor in Chief of the New York University Law Review, where he later served as Adjunct Associate Professor of Environmental Law. He has also been an executive in several other sectors of the non-profit world.

He graduated from Yale, Phi Beta Kappa, magna cum laude, with departmental honours in philosophy. James has worked full time on building ClientEarth since January 2007.