Born in Dallas, Texas, Schell received a B.A. from Southern Methodist University in 1972 and a J.D. from Southern Methodist University in 1975. He was an Instructor, Southern Methodist University Law School from 1975 to 1976. He was an Assistant district attorney of Collin County, Texas in 1976. He was in private practice in McKinney, Texas from 1977 to 1982. He was a judge on the County Court at Law, Collin County, Texas from 1982 to 1986. He was a judge on the 219th Judicial District Court of Texas from 1986 to 1988.