Mark is a member of the litigation and enforcement practice group, where his practice focuses on complex civil litigation and enforcement matters. Mark has represented clients in the healthcare, private equity, and financial services industries, among others, in a wide range of litigation matters including commercial disputes, qui tam litigation, securities class actions, shareholder derivative suits, and products liability claims. He has experience across all stages of civil litigation and alternative dispute resolution proceedings.

During his time at the firm, Mark served for six months as a Special Assistant District Attorney in the Middlesex County, Massachusetts District Attorney’s Office. While there, he prosecuted misdemeanor and felony offenses, including serving as lead counsel on numerous jury trials, bench trials, and evidentiary motions.

Mark maintains an active pro bono practice, representing clients in areas including criminal defense, immigration, and public benefits appeals. Mark serves as co-team lead for income supports matters under the firm’s medical-legal partnership pro bono initiative. 


  • Obtained summary judgment on behalf of major healthcare provider in False Claims Act case alleging billions of dollars in potential liability in connection with alleged regulatory compliance issues.
  • Represented major pharmaceutical company in False Claims Act litigation involving allegations off-label promotion and speaker program kickbacks, obtaining summary judgment and complete affirmance on appeal.
  • Regularly represent and advise private equity firms and their portfolio companies in complex commercial disputes, shareholder derivative actions, third-party discovery matters, and pre-acquisition diligence.
  • Defended large, publicly held consumer goods company in securities class action challenging statements regarding manufacturing capacity and demand projections.
  • Defended major life sciences company against multiple class action and individual lawsuits alleging products liability claims and violations of state consumer protection statutes. Helped to achieve complete dismissal of class action claims in federal district court.
  • Represented major pharmaceutical company in intervened False Claims Act litigation involving allegations of fraudulent Medicaid price reporting.
  • Representing managed Medicaid health plan in False Claims Act litigation involving allegations of kickbacks to providers and failure to apply adequate utilization review controls.
  • Commonwealth v. Celester - Counsel for Massachusetts Association of Criminal Defense Lawyers in amicus brief addressing the right to effective assistance of counsel in pre-arraignment custodial interrogation.

Areas of Practice