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John A. Sheehan



With more than 30 years of experience in environmental law and litigation, John brings a unique background and perspective to his role as a partner at Michael Best from having served in government at the United States Department of Justice and now representing clients in private practice.

John defends clients in enforcement actions brought by regulatory agencies and environmental groups. His knowledge of the regulatory landscape allows him to help clients with regulatory issues at the federal and state levels. He currently works with drinking water and wastewater trade associations on critical issues to the members they represent. 

John’s litigation experience includes representing private industry, state and municipal governments, and trade associations in environmental litigation in federal courts throughout the country, and in regulatory proceedings at the federal and state levels. He notably represented the State of Florida in its lawsuit against BP, arising out of the Deepwater Horizon disaster.


Earlier in his career, John was a senior trial attorney at the U.S. Department of Justice in Washington, D.C. in the Environment and Natural Resources Division. He was the lead trial attorney for the United States in major, precedent-setting litigation for the department. He was involved in several precedent setting cases under the Clean Water Act, the Clean Air Act, and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). He served as the lead trial lawyer for the U.S. Environmental Protection Agency (EPA) in litigation brought by the tobacco industry related to secondhand tobacco smoke.

After his government service and prior to joining Michael Best, John practiced in Washington, D.C. and Richmond, Virginia with national firms, where he represented a variety of clients in environmental litigation and counseled private industry clients in enforcement defense cases and transactional deals under key environmental statutes.

John also was previously a partner with a boutique environmental law firm that specialized in federal and state water quality issues where he counseled municipal and private industry clients on regulatory and compliance issues. He served as lead counsel in litigation for national association clients in federal courts and assisted communities in defense of enforcement actions by the U.S. Department of Justice for combined sewer overflow system violations.


  • Represented a state natural resources trustee in the recovery of natural resource damages arising out of the Deepwater Horizon disaster. Helped negotiate the largest settlement of an environmental case in history.
  • Represents a state enforcement agency in the federal district court, proving liability under CERCLA for certain damages in a several million dollar dispute
  • Represented the operator of a public water utility in defending claims for liability at the federal district court, reaching a favorable settlement
  • Represents a national trade association of drinking water systems in federal appellate court, challenging an EPA rulemaking on discharges by steam electric power generating facilities
  • Represented an ink manufacturer in defense of a claim of environmental liability, reaching favorable settlement of the enforcement matter
  • Successfully represented a client in a two week jury trial in Superior Court in D.C. defending a claim for defamation
  • Represented a county government’s road commission in ongoing litigation regarding obtaining environmental permits for a large road project

Honors & Recognitions

  • Special Achievement Award, U.S. Department of Justice, 1994 and 1997
  • Special Merit Award, U.S. Environmental Protection Agency Office of General Counsel, 2001

Professional Activities

  • Executive Committee Member, U.S. Chambers of Commerce’s Business Task Force on Water Policy
  • Member, Environmental Section, Maryland State Bar, 1985-Present
  • Member, Environmental Section, District of Columbia Bar, 1986-Present
  • Member, American Bar Association



Community Involvement

  • Volunteer Coach, Youth Basketball
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