Mark P. McMahon grew up in Henderson, Texas and graduated from Henderson High School. After receiving his BBA from the University of Texas at Austin in 1974 and a JD in 1976 from St. Mary's University of San Antonio, Mark was licensed to practice in Texas in 1977.
While at St. Mary's Law School, Longview personal injury lawyer Mark was a member of the Phi Delta Phi Honorary Legal Fraternity and was Associate Editor of St. Mary's Law Journal (1975-1976). After graduating, he served as Staff Counsel, Judiciary Committee, Texas House of Representatives (1977); and as Briefing Attorney, Sixth Court of Civil Appeals, Texarkana, Texas (1977-1978).
He has practiced in state and federal courts since 1977, and received his license to practice before the U.S. District Court, Eastern District of Texas in 1979; the U.S. Court of Appeals for the Fifth Circuit in 1980; the U.S. District Court, Western District of Texas in 1983; and the United States Supreme Court 1984.
Mark has been a member of the State Bar of Texas since 1977, and is long-standing member of the Gregg County Bar Association, Northeast Texas Bar Association, East Texas Trial Lawyers Association, (V.P., 1989-1991; President, 1991-1993), Texas Trial Lawyers Association (V.P. Communications; Director), and the American Association of Justice.
He is a member of the College of the State Bar of Texas, and is a Fellow of the Texas Bar Foundation and of the Roscoe Pound Foundation. Mark is a member of the American Board of Trial Advocates (ABOTA). Mark is certified by the Texas Board of Legal Specialization in the area of Personal Injury Trial Law.