Huger fought notably in 1846–48 during the Mexican–American War, serving as chief of ordnance on the staff of Maj. Gen. Winfield Scott throughout the conflict. Huger had command of the siege train during the Siege of Veracruz, March 9–29, 1847. He was appointed to the rank of brevet major for his performance at the Veracruz on March 29, and to lieutenant colonel for the Battle of Molino del Rey on September 8. Huger was brevetted a colonel five days later for "gallant and meritorious conduct" during the storming of Chapultepec.