John Masslon is a Counsel at Keller Postman LLC. He enjoys using his broad appellate experience to ensure that legal issues are resolved in a manner that leads to just outcomes for clients.

At Keller Postman, John works on a broad range of disputes, including products liability and consumer protections suits. John helps develop legal strategies, writes briefs, and presents argument on legal questions. He also uses his econometrics training to help with expert discovery and examination.

John recognizes the importance of pro bono work. Recently, he has won two appeals that ultimately granted his client state post-conviction relief. He also has helped Catholic non-profits with corporate issues.

Before joining Keller Postman, John was senior litigation counsel at Washington Legal Foundation. There, he wrote about 100 amicus briefs supporting free enterprise in courts across the country. He filed the first amicus brief in the Supreme Court supporting the challenge to OSHA’s vaccine mandate, which helped convince the Court to take the extraordinary step of hearing argument and staying the mandate.  He also filed a brief supporting ending the unconstitutional in-house proceedings at the Securities and Exchange Commission.

Previously, John served as assistant solicitor general in a state attorney general’s office. There, he was first chair in a federal trial challenging a state election law that was ultimately upheld. He also wrote the briefs that convinced the state supreme court to uphold the State’s right-to-work statute. This experience helps John understand the nuances of working with state attorneys general.

John obtained his B.S. in economics with a minor in mathematical sciences from Clemson University. He then received his J.D. and LL.M. in Taxation from Georgetown University Law Center. After law school, John worked for Judge Arthur J. Schwab of the United States District Court for the Western District of Pennsylvania and clerked for Judge Judith Ference Olson of the Superior Court of Pennsylvania.

John is licensed to practice law in the District of Columbia, New York, Pennsylvania, and West Virginia.

Quote

"My most memorable moments as an attorney involve telling clients that we had won appeals in important cases. I’ll never forget calling a client as I stood outside the British Museum and telling him the good news. Nor will I forget receiving an after-hours order and running down the hall and telling my client the good news!"

John Masslon

Education & Clerkships

  • J.D. and LL.M., Georgetown University Law Center
  • B.S., Clemson University
  • Clerkship: U.S. District Court for the Western District of Pennsylvania
  • Clerkship: Superior Court of Pennsylvania

Previous Affiliations

  • Washington Legal Foundation
  • Office of the West Virginia Attorney General