Mr. Matthiessen has been Hudson Riverkeeper & President since July, 2000. He has guided Riverkeeper’s transformation into one of the country’s most respected local environmental advocacy groups. Under his tenure, Riverkeeper has undergone a period of pronounced growth with more than a doubling in staff, an eight-fold increase in membership, and a quadrupling of the budget, reflecting more robust and diversified funding streams.

Mr. Matthiessen has instituted a full-time enforcement presence on the Hudson River and its tributaries and has expanded the organization’s reach from points north of Albany down to and including all of New York Harbor. While strengthening Riverkeeper’s enforcement capacity, Mr. Matthiessen also has been pursuing strategies to develop long-term, preventative approaches to environmental problem solving

Under his direction, Riverkeeper has forged partnerships with leading academic and research institutions such as Lamont-Doherty Earth Observatory, Columbia University School of Law, and Columbia University Graduate School of Architecture, Planning and Preservation. These partnerships are serving to strengthen Riverkeeper’s enforcement efforts, advance our scientific understanding of the Hudson River, and identify solutions to poorly planned development along the Hudson River corridor.

Prior to joining Riverkeeper, Mr. Matthiessen was Special Assistant at the U.S. Department of the Interior, focusing on matters of special importance to Department Secretary Bruce Babbitt. He oversaw a government-wide task force to reform the Federal Energy Regulatory Commission's hydropower licensing process. He also conceived and developed the Green Energy Parks initiative, a joint program of the National Park Service and the Department of Energy, which promotes clean and sustainable energy use throughout the national park system. For his leadership on the project, Mr. Matthiessen received a Presidential Award from the White House.

Earlier in his career, Mr. Matthiessen was a Macroeconomic Policy Analyst in Indonesia for the Harvard Institute for International Development, and worked at the White House Council on Environmental Quality. He also served as the Grassroots Program Director for the Rainforest Action Network in San Francisco, organizing and managing an international network of affiliate activist groups. He holds a Masters of Public Administration from the John F. Kennedy School of Government at Harvard University, and earned a BA (Biology and Environmental Studies) from the University of California at Santa Cruz.

Mr. Matthiessen served on New York State Governor Eliot Spitzer’s transition team as an advisor on energy and environmental policy goals, and is chair of the energy committee for Westchester County’s task force on climate change. He is also on the boards of directors of Catskill Mountainkeeper and Waterkeeper Alliance, the umbrella organization for the more than 150 Keeper programs working to protect local water resources around the world.