Before joining Puget Soundkeeper as its Executive Director, Sean worked at the U.S. EPA as the Region 1 (New England) Chief of Staff, as a Senior Attorney at Hudson Riverkeeper in New York City, and as a coastal policy attorney with Clean Ocean Action on in New Jersey. Sean has also been an Adjunct Professor of Law at Pace Law School in White Plains, NY, a Lecturer at Yale College in New Haven, CT, and as a fisheries enforcement observer in Alaska. Sean also co-founded and co-ran Village Fishmonger, a NYC-area sustainable, local seafood wholesale business. Sean has a JD and LLM from Pace Law, MEM from Yale School of Forestry and Environmental Studies, and a BA in Marine Science from Boston University.

Sean has volunteered with the American Bar Association's Section of Environment, Energy, and Resources, including service a three year posting on the Section's governing Council, and one year as the Section's Membership Officer. Sean also spent 4 years as a volunteer dive team leader on the New York Aquarium's Volunteer Dive Team.