When a Confederate colonel called John Clem a "damned little Yankee devil" and demanded his surrender at the Battle of Chickamauga, John shot him — and became the youngest noncommissioned officer in U.S. Army history John Clem was barely four feet tall when he joined the Union Army during the Civil War In May 1861, U.S. President Abraham Lincoln sent out a national call for volunteers to fight for the Union Army. Many eagerly rose to the occasion, including one unlikely soldier: a nine-year-old boy named John Clem. Standing at just four feet tall, Clem first tried to volunteer for...