Mary Hennessey is a tax attorney who advises clients on corporate and partnership taxation matters, including mergers and acquisitions, federal taxation of real estate transactions, entity structuring, income tax planning, and tax-exempt entities.

Mary is also a member of Honigman’s Emerging Companies Group.



Representative Matters

  • Drafted organizational documents such as operating agreements containing intricate partnership tax-distribution and -allocation provisions

  • Counseled clients in transactions involving tax incentives including New Market Tax Credits, Historic Tax Credits, and Opportunity Zones

  • Represented tax-exempt entities in formation, governance and real estate joint ventures with for-profit entities

  • Litigated state and local tax controversies resulting in settlement agreements with values to clients in excess of $100 million

  • Served as an intern in the Civil Rights Unit of the U.S. Attorney's Office for the Eastern District of Michigan
  • Served as a judicial intern to the Honorable Nancy G. Edmunds, U.S. District Court for the Eastern District of Michigan

Prior Experience

  • Dykema Gossett PLLC, Associate, 2013-2017






The Best Lawyers in America

  •  Recognized in the practice area of Corporate Law, 2023

Professional & Community Involvement

Michigan Women's Tax Association, Program Committee

State Bar of Michigan, Tax Section

Community Foundation for Southeast Michigan, Professional Advisors Philanthropic Institute

News & Insights

Press Releases


  • Buying and Selling a Business in Michigan, Second Edition, Tax Considerations Chapter
  • International Boycott Reporting
    Publication | Michigan Tax Lawyer Issue 3 | Summer 2014

Seminars & Events

  • New Special Business Income Tax Deduction
    Event | | | Presenter
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