Mitchell is Principal at Mitchell Law PLLC and served as Solicitor General of Texas from 2010 to 2015. He previously worked as an Attorney-Adviser in the U.S. Department of Justice Office of Legal Counsel from 2003 to 2006 and has held faculty positions at Georgetown University Law Center, the University of Chicago Law School, George Mason University School of Law, the University of Texas at Austin School of Law, and Stanford Law School. Mitchell has argued eight cases before the U.S. Supreme Court and more than 20 cases in the federal courts of appeals. He clerked for Judge J. Michael Luttig of the U.S. Court of Appeals for the Fourth Circuit and for Justice Antonin Scalia of the Supreme Court.