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Sean Marciniak

Sean R. Marciniak

(925) 746-8471


Sean is the leader of Hanson Bridgett's Land Use Practice Group, and has specialized in land use and environmental law for more than a dozen years. He is a former newspaper reporter and investigator for the State of Texas, and combines skillsets from across disciplines to find creative legal solutions for his clients. In concert with his team, he counsels landowners, developers, and public agencies on all aspects of environmental and land use matters, and regularly appears at administrative hearings throughout the State of California. Having experience in both land use entitlement and litigation, he is forward-thinking in designing strategies for the permitting and environmental review of development projects, and engineers approaches to maximize efficiency and defensibility while minimizing costs and delays.

Sean and his team have helped entitle millions of square feet of development in California, including affordable housing projects, wineries and vineyards, mixed-use development, regional hospitals, laboratories, pharmaceutical campuses, shopping centers, office campuses, infrastructure projects, terminal expansions and intermodal transport facilities at California’s busiest ports, and solar energy projects. These projects have been located throughout California, from Humboldt County to San Diego. Areas of focus include counseling under the California Environmental Quality Act, the National Environmental Policy Act,  Planning and Zoning Law, the Subdivision Map Act, takings and exactions, development agreements, initiatives and referendums, Local Agency Formation Commissions, the Housing Accountability Act, natural resource permitting (including under the Endangered Species Act and Clean Water Act Sections 401 and 404), and emerging laws addressing climate change and sustainable development.

Prior to joining Hanson Bridgett, Sean was a shareholder at Miller Starr Regalia, where he helped write and edit sections of land use practice guides including Miller & Starr, California Real Estate 4th, a 12-volume treatise on California real estate law. He began his legal career in the environmental and land use practice at an international law firm where he edited and wrote sections of other land use treatises and practice guides used across the state. As a journalist, Sean was a crime and investigative reporter in the Texas borderlands. His articles have appeared in publications that include The Wall Street Journal, the Dallas Morning News, and the Houston Chronicle, and have merited awards from the Associated Press and Bloomberg News. As an investigator in the State of Texas, Sean looked into allegations of judicial misconduct for the State Commission on Judicial Conduct.


J.D. University of California, Berkeley School of Law ( 2007 )
M.A. University of California Graduate School of Journalism ( 2004 )
B.A. Brandeis University ( 1999 )

Admissions and Courts



Land Use Practice Leader
Air Quality Practice Leader

American Bar Association

Bay Planning Coalition, Former Board Member

Contra Costa County Bar Association

Urban Land Institute

Rising Star, Super Lawyers Northern California (2012–2017)