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Mary Kate Mullen

Mary Kate Mullen

Senior Associate

Mary Kate takes a service-first approach to representing clients in complex healthcare disputes in federal and state courts.

Mary Kate is involved in every stage of commercial and healthcare litigation and acquired significant trial and oral argument experience early in her career. A graduate of the National Association of Railroad Trial Counsel (NARTC)’s trial college program, she has built a strong reputation as a highly prepared litigator who knows case law backwards and forwards and who remains calm under great pressure.

Mary Kate brings a bevy of skills to her advocacy for clients. Her approachable, unassuming demeanor allows for easy collaboration among clients, witnesses and counsel, yet her competitive nature shines in the courtroom. A skilled writer, she brings injunctive and other extraordinary relief for clients through well-written motions and compelling briefs. She’s known for her ability to see both sides of cases, allowing her to anticipate opposing arguments and a judge’s reaction, as well as spot and correct flaws in her own arguments.

With a passion for the healthcare industry, Mary Kate devotes the majority of her practice to healthcare providers, hospitals, nursing care facilities, suppliers and pharmacy benefit managers. She advises and defends clients in business-critical cases, including malpractice allegations, breach of contract litigation, wrongful death lawsuits and employment matters. Mary Kate understands how challenging healthcare work can be and values the opportunity to support providers.

At the end of the day, Mary Kate would simply describe her role as helping people through difficult situations. She knows litigation is stressful and frightening, sometimes putting a client’s entire organization on the line, and her goal is to provide full support. Her approach always keeps service front and center: Mary Kate knows clients want different things and have different goals for litigation, and she seeks to develop strategic solutions that fit individual client needs.





  • J.D., Saint Louis University School of Law
    • cum laude
    • Saint Louis University Law Journal
  • B.A., Rhodes College
    • cum laude
    • History
    • NCAA All-American


  • Missouri
  • Illinois
  • U.S. District Court, Eastern District of Missouri

Professional Memberships and Certifications

  • The Bar Association of Metropolitan St. Louis
  • Missouri Bar Association
  • Women Lawyers’ Association of Greater St. Louis
  • National Association of Railroad Trial Counsel


The Hon. Kurt S. Odenwald, Missouri Court of Appeals, Eastern District, 2016

2023 Pro Bono Achiever
  • Obtained a defense verdict after a week-long jury trial on behalf of The Kansas City Southern Railway Company in a case brought under the Federal Employers' Liability Act (FELA).
  • Procured favorable settlement on behalf of plaintiff in complex pharmacy rebate breach of contract litigation.
  • Won case dismissals in nursing home discharge administrative hearings.
  • Successfully defended temporary restraining order filed against pharmacy benefit manager in federal court.
  • Successfully won motion for summary judgment in complex arbitration on behalf of pharmacy benefit manager.
  • Obtained highly favorable settlement for pharmacy benefit manager after plaintiff made multimillion-dollar demand.
  • Obtained defense verdict after week-long jury trial in wrongful death case in St. Louis County.
  • Co-investigated alleged incidents of disability discrimination in university athletics.
  • Co-investigated alleged incidents of sexual harassment in university athletics.
  • Obtained favorable result from the Missouri Court of Appeals when the Court of Appeals affirmed a jury verdict in favor of anesthesia provider client.
  • Won order striking defendant's pleadings and default judgment in breach of contract action.
Outside the Office

Mary Kate is a proud supporter of all things St. Louis.

She is especially drawn to the arts and theater scene. Mary Kate formerly worked at The Muny outdoor musical theater – a St. Louis treasure – and frequently attends live performances around town. She and her husband actively support local businesses and restaurants and are contributing members to the Missouri Botanical Gardens.

Mary Kate also enjoys reading historical fiction, hitting the gym and visiting St. Louis parks with her Clumber Spaniel, Thea.

Community Leadership

Mary Kate has an active pro bono practice. She represents low-income families, victims of domestic violence and indigent clients through the firm’s relationship with Grace Hill Settlement House.

  • St. Louis Hills Neighborhood Association
  • St. Gabriel the Archangel Catholic Church Parish
  • Cor Jesu Academy, Mock Trial Coach
  • Peter & Paul Community Services, Board Member