John Grayson was born in Kentucky in 1806 to Alfred W. Grayson and Letitia Breckinridge at the
Breckinridge family estate of "Cabell's Dale". After his father's death when he was around ten Grayson's mother married
Peter Buell Porter. Grayson was appointed to
West Point through his ties to three very powerful families the Breckinridges, Graysons, and Porters. He graduated in 1826 and became a second lieutenant in the artillery. He was first assigned to
Fort Monroe where he remained for six years. He then served in a variety of southern forts from 1832 to 1835. In 1835 the
Second Seminole War broke out in Florida. Grayson fought at Camp Izard and then at the Battle of Oloklikaha. After the Seminole War, Grayson was assigned to New Orleans for eleven years. In 1847 Grayson left to fight in the
Mexican-American War where he arrived as a captain of the artillery. Grayson later became the Chief Commissariat of Major General
Winfield Scott. Grayson fought in many battles in Mexico including the
Siege of Veracruz,
Battles of Cerro Gordo,
Contreras,
Churubusco,
Molino del Rey,
Chapultepec, and the
capture of Mexico City. He became a major for his bravery at the battles of Contreras and Churubusco in 1847. Later that year Grayson was
brevetted to lieutenant-colonel for his actions at the
Battle of Chapultepec. After the war he was assigned to Detroit, Michigan where he became the Chief of Commissariat for seven years from 1848 to 1855. He would hold this same title in New Mexico until he resigned to join the
Confederate Army. ==Civil War service==