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William E. Keenen focuses his practice primarily on estate planning for high-net-worth individuals and their families. He works with business owners, private equity fund managers, C-suite executives and other individuals of various backgrounds in business, as well as individuals in the sports and entertainment sectors, to pursue their multigenerational wealth transfer objectives. In furtherance of that planning, William prepares wills, trusts and a variety of other instruments, including prenuptial and postnuptial agreements, and, where appropriate, creates more sophisticated estate planning structures. He routinely advises clients who are relocating from high-income-tax jurisdictions within the United States.

William also counsels clients with respect to the day-to-day administration of trusts and estates, including in matters involving post-mortem tax planning. He has assisted individual and corporate fiduciaries, as well as beneficiaries, in litigated trust and probate matters.

In addition, William has represented clients in tax controversies and other tax matters before the Internal Revenue Service (IRS), including matters of U.S. income, estate, gift and generation-skipping transfer (GST) taxation, and, early in his career, offshore voluntary disclosures. He has also assisted clients with the formation and operation of private foundations.

William has written about and lectured on various transfer tax topics affecting high-net-worth individuals and their families, including in the areas of shifting domicile within the United States, allocations of GST exemption and the application of the U.S. estate and gift tax law to transfers of property by citizens and non-citizens of the United States.


  • Multigenerational wealth transfer planning
  • Estate, gift and GST tax matters and controversies before the IRS
  • International estate planning
  • Prenuptial and postnuptial agreements
  • Trust and estate administration and litigation
  • Business succession planning
  • Private foundations


Recognition & Leadership

  • Listed, The Best Lawyers in America, "Ones to Watch," Tax Law; Trusts and Estates, 2021-2024
  • Listed, South Florida Legal Guide, "Top Up-and-Comer," 2020-2022
  • Estate Planning Counsel of Central Texas, 2023-Present
  • Trust and Estate Practitioner (TEP), Society of Trust and Estate Practitioners (STEP), Miami Branch, 2018-Present (Technician Member, 2014-2018)
  • Member, Brickell Avenue Literary Society, 2018-2022
  • Member, Young Professionals (formerly the Upper Room), Miami City Ballet, 2017-2020
  • Member, Tax Section of The Florida Bar, 2012-Present
  • Event Chair, Don Q Crash the Gala, Miami City Ballet, 2019-2020
  • Member, 2020 Gala Committee, Miami City Ballet, 2019-2020
  • Graduate (LM Class 40), Leadership Miami, Greater Miami Chamber of Commerce, 2018-2019
  • Member, The Grand Finale Steering Committee, Miami City Ballet, 2018-2019
  • Graduate (Class II), Florida Fellows Institute of the American College of Trust and Estate Counsel (ACTEC), 2017
  • Participant, OutLeadership’s OutNEXT Summit, 2016
  • Mentor, Big Brothers Big Sisters of Greater Miami, School to Work Program, 2014-2016
  • Tax Law Clerk, Legal Services of Greater Miami, Inc., 2012


  • LL.M., Taxation, University of Miami School of Law
    • Recipient, Dean's Certificate of Achievement Award, Taxation of Business Entities: Partnership
    • Recipient, Merit Scholarship
  • J.D., cum laude, University of Miami School of Law
    • Recipient, C.A.L.I. Excellence for the Future Award for Family Law
    • Recipient, Dean's Outstanding Public Interest Scholarship
  • B.S., summa cum laude, Sam Houston State University
  • Florida
  • District of Columbia
  • Texas
  • U.S. Tax Court