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John Tamasitis, Williams Mullen Headshot

John G. Tamasitis

Senior Associate
Columbia, SC
  • T.
  • 803.567.4617
  • F.
  • 803.567.4601

John Tamasitis is a trial lawyer who has represented clients in state and federal trial and appellate courts in a variety of complex commercial litigation matters. These matters include products liability lawsuits, mass torts, white collar criminal defense, business contract disputes, zoning and regulatory matters that involve constitutional claims, and environmental litigation. 

John is a former federal law enforcement agent and Air Force officer who has extensive experience guiding corporate clients in a variety of matters involving commercial contracts, construction defects, corporate insolvency, and both state and federal constitutional matters. 

John is also a part of Williams Mullen’s firearms practice, which represents members of the firearms industry, including manufacturers, retailers, and government contractors. The firm also assists businesses outside the firearms industry with matters such as the unique issues faced by lenders to firearms industry and employers who must implement policies regarding employees’ possession and use of firearms.

John is focused on assisting clients throughout the litigation process, from pre-litigation strategy and guidance through settlement negotiations, arbitration, trials and appeals to the South Carolina Supreme Court and the United States Court of Appeals for the Fourth Circuit.

Prior to practicing law, John served as a captain in the United States Air Force with the Office of Special Investigations. While deployed, John led counterintelligence and counterinsurgency teams in Afghanistan in 2008 and 2009 and was awarded the Bronze Star for his service in and around Bagram Airfield. Back in the United States, John operated as a counterintelligence agent and was the appointed branch chief for two Air Force bases in Northwest Florida until heading off to law school in late 2011. In that role, John led and directed a team responsible for counterintelligence/anti-terrorism investigations in the area. He also provided research and technology counterintelligence protection services with the FBI and other government agencies to the Air Force's Special Operations Headquarters and the Air Force Research Laboratory Munitions Directorate, which conducts research and development for the Air Force's air-launched munitions and explosives program.

John is an active participant in his community, serving as a founding member and president of Midlands Junior Golf Foundation.

John received his law degree from the University of South Carolina School of Law, magna cum laude, where he was both a member of the Order of the Coif and the Order of the Wig and Robe. During law school, John served as the Fourth Circuit Editor of the South Carolina Law Review. John earned his Bachelor of Science degree from the U.S. Air Force Academy where he was the class president and a cadet squadron commander.

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  • University of South Carolina School of Law (J.D.), 2014
    • magna cum laude
    • Order of the Coif and Order of the Wig and Robe
  • United States Air Force Academy (B.S.), 2005
Professional & Community Affiliations

Professional Affiliations

  • South Carolina Bar - Military and Veterans Law Section, Immediate Past Chair and Section Delegate
  • Richland County Bar Association
  • Litigation Skill Committee - Member to Defense Research Institute
  • South Carolina Defense Trial Attorneys' Association
  • Defense Research Institute

Community Involvements

  • Midlands Junior Golf Foundation - Founding Member and President
Bar & Court Admissions

Bar Admissions

  • South Carolina State Bar

Court Admissions

  • District Court for the District of South Carolina
  • Fourth Circuit Court of Appeals
  • South Carolina Supreme Court

Best Lawyers in America® "Ones to Watch" - Commercial Litigation (2021-present)

Columbia Business Monthly - "Legal Elite," Bankruptcy & Creditors' Rights (2020)

Bronze Star Medal


While most clients generally prefer to avoid litigation, the ability to present a willingness to protect a company’s rights in court is an important component of any corporate risk management program. John’s experience and creative analytical abilities, backed by extensive courtroom experience, have been relied upon when clients have been forced into litigation in difficult jurisdictions.
Representative experiences include the following:

  • Lead trial counsel representing international real estate investment trust in constitutional litigation against local municipality.
  • Member of trial team for international industrial personal protective equipment manufacturer in products liability wrongful death litigation. 
  • Defended commercial lender in state court trial defending validity of mortgage against heirs in historic neighborhood in downtown Charleston.
  • Lead counsel representing international real estate investment trust in constitutional litigation against local municipality.
  • Represented mining companies in challenges to permitting efforts by government entities and environmental advocacy rights groups.
  • Part of team representing municipality in Chapter 9 bankruptcy proceedings.
  • Defense of commercial litigation relating to commercial roofing systems, representing large manufacturer and supplier of roofing products.
  • Defended national human services provider in wrongful death litigation.
  • Assisted utility in the acquisition of access and easement rights for two natural gas pipelines through negotiation and litigation in state and federal courts.
  • Represented national commercial insurance provider in coverage dispute in federal court.
  • Represented firearms industry members regarding ATF inspections and investigations, and potential regulatory action stemming from such inspections and investigations.
  • Advised e-commerce retailers on terms and conditions of firearms sales over internet and on challenges posed by shipping to states and localities that restrict firearms and ammunition sales.
  • Represented federal firearms licensee in license revocation proceedings.
  • Provided advice to firearms industry members regarding marketing practices and relationships in light of restrictions on marketing to the firearms industry imposed by state legislatures.
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