John Marck

On April 01, 2026, President Trump nominated John Marck to the United States District Court for the Southern District of Texas. He was confirmed on June 24, 2026.

Biography

Marck received a B.A. from Brooklyn College, City University of New York in 2009 and a J.D. from St. John’s University School of Law in 2013.

Legal Experience

After graduating from law school in 2013, Marck served as a special assistant district attorney in the Brooklyn District Attorney’s Office. He then served as an assistant district attorney in the Bronx District Attorney’s Office from 2014 to 2021. In 2021, he joined the U.S. Attorney’s Office for the Southern District of Texas as an assistant U.S. attorney. In early 2026, he was named acting U.S. attorney for the Southern District of Texas.

Key Facts 

Professional and Legal Associations

Republican National Lawyers Association (2025–present); The Federalist Society (2011–present); Christian Legal Society (2011–present); Bar Association of the Fifth Circuit (2023–2025); New York State Bar Association (2015–2016); President, St. John’s University School of Law Student Chapter of the Federalist Society (2012–2013).

• During his time as an assistant district attorney in New York, Marck’s caseload primarily consisted of major felonies, including murder, manslaughter, robbery, and gang assault.

• At the beginning of his tenure at the United States Attorney’s Office for the Southern District of Texas, Marck was responsible for handling a significant number of immigration-related cases.

• In 2025, Marck was promoted to Associate Deputy Criminal Chief of the National Security/Public Corruption Section of his office, a role in which he prosecuted national security, counterintelligence, and cybercrime cases.