Mr. Weir helps clients litigate constitutional, statutory, and regulatory issues in courts and agencies throughout the country. He has represented a broad range of clients on matters of constitutional law, administrative law, civil rights disputes, election law, and complex commercial disputes. In addition to his practice before trial courts and arbitrators, Mr. Weir has significant appellate experience. He has been the lead drafter of briefs before the Supreme Court of the United States and has contributed to multiple wins before the Court.

Mr. Weir is a former law clerk to Judge Carlos T. Bea of the United States Court of Appeals for the Ninth Circuit and Judge Anthony J. Trenga of the United States District Court for the Eastern District of Virginia. Since 2015, Mr. Weir has been an adjunct professor for the Administrative Law and Supreme Court Clinics at the Antonin Scalia Law School at George Mason University.

Mr. Weir earned his A.B. cum laude from Georgetown University and his J.D. summa cum laude from George Mason University School of Law. Mr. Weir is a member of the Virginia and California bars.