William “Bill” Seitz has been part of the Miami, Florida community since moving here from Iowa in 2006 to attend law school at the University of Miami. Midwest upbringing and his immersion in South Florida living and involvement in the community helps shape his law practice. Since becoming a full-time resident in South Florida with his family, Bill has taken an active role in the local community, partnering with such organizations as Lotus House, Nicklaus Children’s Hospital and Leadership Miami. Bill believes in being an aggressive litigator and advocate for his clients while still making sure to maintain a personal, friendly touch with both them and the opposing side

Bill’s diverse background is not just limited to his upbringing and current residence in Miami. He has a unique mix of life, education and work experiences that separates him from other attorneys. Bill received his B.B.A. in Finance from the University of Iowa in 2006, which laid the foundation for his work in complex business litigation after earning his Juris Doctor, from the University of Miami School of law in 2009.

Bill originally got his trial experience working on commercial claims representing financial institutions across Florida.  Over the years, Bill expanded his practice from only working on commercial matters to also working in tort and personal injury law. In 2013, Bill took an interest in Mase Mebane Seitz’s industry leading maritime trial practice and joined the firm.  Bill brought his years of commercial trial experience and expanded that into the field of maritime and personal injury trial work. Bill quickly worked his way up the ranks to become a shareholder. While Bill has more than a decade of working for his commercial clients, his trial practice now also includes substantial work doing wrongful death and personal injury work with a particular interest in cruise ship and maritime related law. His original background as a commercial litigator makes him perfectly suited to expand his practice to higher profile cases like class actions, whistleblower (qui tam) cases, and deceptive trade practices cases where he brought claims on behalf of individuals and corporations.

Many cases that Bill works on are contingency fee-based, meaning Mase Mebane Seitz only gets paid if the client gets money. This makes him feel that the client and he are in it together as a team. Because of this, Bill still takes on some complex commercial cases and will consider flexible and unique fee arrangements if the client and claim make sense to him. The driving force behind Bill’s passion for practicing law is the challenge of litigation and finding solutions to unique claims and problems for his clients, helping out people in the Miami community, and working closely with his colleagues at Mase Mebane Seitz.


University of Miami School of Law

J.D., magna cum laude, 2009

The University of Iowa Henry B. Tippie College of Business

B.A. Finance, with distinction, 2006

Bar Admissions & Certifications

  • Florida
  • U.S. District Court, Southern District of Florida
  • U.S. District Court, Middle District of Florida
  • U.S. Court of Appeals, 11th Circuit

Honors & Recognition

  • Million Dollar Advocates Forum
  • Super Lawyers “Rising Star”, 2015-2019
  • Super Lawyers, 2021-Present
  • South Florida Legal Guide, Top Up and Comers, 2020-2021
  • Best Lawyers: Ones to Watch, 2021

Areas of Practice & Representative Cases

Lucas v. Royal Caribbean Cruises, Ltd.; 19-20914



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Membership & Community Involvement

  • Dade County Bar Association
  • The Florida Bar Admiralty Law Committee, 2019-present
  • The Florida Bar Grievance Committee, Committee K, 2015 to 2017, Chair in 2017
  • Leadership Miami – Greater Miami Chamber of Commerce, Class of 2016
  • Coconut Grove, Florida Chamber of Commerce
  • Nicklaus Children’s Hospital Young Professionals