Timothy Williamson worked with the U.S. Environmental Protection Agency for over 35 years, most notably as their Deputy Regional Counsel. Williamson served as Deputy Regional Counsel in Region I from 1993 to 2020. In that position he was primarily responsible for overseeing staff working on the Clean Air Act, Indian law, information law, appropriations law, and employee and labor relations law. Prior to starting at the EPA, Williamson gained experience working as an associate Palmer & Dodge, a Boston law firm.

When he started at the EPA in 1985, Williamson began as Assistant Regional Counsel before moving into a Senior Policy Analyst role, then Acting Chief of the Air Quality Planning Unit, and finally Acting Human Resources Officer. Williamson has a passion for Environmental Law topics, and in addition to New England Law, has also taught at Boston University School of Law, Boston College Law School, and the Harvard School of Public Health.