John Greffet is a respected trial attorney with more than a decade of experience handling complex claims involving car accidents, trucking crashes, wrongful death, premises liability, medical malpractice, and consumer protection. He is committed to aggressive advocacy for his clients, handling cases from the initial investigation and claims phase all the way through trial and into the appellate level. He has extensive experience trying cases in both federal and state courts, as well as in appellate courts throughout Missouri and Illinois.

“I truly appreciate being able to make real concrete changes in people’s lives,” he says. “That can mean anything from obtaining a financial recovery for someone who really needs it, to holding negligent people and businesses accountable for their actions, to just being there to listen when a client needs to talk about what they’re going through.”

John and the rest of the team at Sumner Law Group, LLC, are committed to outstanding customer service. “We are an extremely collaborative and supportive group. Every member of our team is there to pitch in whenever and however they are needed,” he says. “As a result, we’re able to offer our clients superior service and results.”

Growing up in St. Louis, John always had a natural talent for debating and arguing. “Initially, the practice of law seemed like it would be a good fit for me because, growing up, I was the sort of person who loved to debate and argue about all sorts of issues, big and small,” he says. “As I got older, I realized that lawyers have a unique opportunity in our society to shape the laws that govern our day-to-day lives and ensure that those laws are fairly and equitably enforced. As a trial lawyer, I have the opportunity to do just that for each client I represent.”

John earned his B.S. in political science from Southern Illinois University-Edwardsville in 2006. He then went on to earn his J.D. from Saint Louis University School of Law in 2009. He is a member of the Missouri Bar Association, the Missouri Association of Trial Attorneys, and the Bar Association of Metropolitan St. Louis.

Outside of his legal practice, John enjoys spending time with his wife and two small children, travelling, and playing golf. He also volunteers with the Holiday Hearts Program at the Crisis Nursery St. Louis, an organization that provides a short-term safe place to stay for children whose families are facing crisis.


  • B.S. in political science from Southern Illinois University-Edwardsville, 2006
  • J.D. from Saint Louis University School of Law, 2009

Professional Associations

  • Missouri Bar Association
  • Missouri Association of Trial Attorneys
  • Bar Association of Metropolitan St. Louis
  • Illinois State Bar Association