A successful lawyer, Leedy was also regularly involved in military matters, serving with the Virginia Volunteers (National Guard) for many years. In September 1902, he was made a captain of the "Page Rifles," which was an unassigned militia company in Luray until mustered in as Company C of the 2nd Virginia Regiment, Virginia National Guard. Leedy quickly rose in the regiment, being promoted to lieutenant colonel in June 1905 and full colonel by August of the same year. In June 1916, the 2nd Regiment was one of a number called up from the National Guard in a Border support role in support of the Pancho Villa Expedition. He continued to command the regiment during its nine-month stay near the Mexican border, at Brownsville, Texas. Not long after the regiment returned to Virginia, it was called up again for service when the United States committed to participation in the First World War. When the regiment was sent to Camp McClellan, Alabama in preparation for shipment overseas as part of the American Expeditionary Force, it was combined with the 1st and 4th Virginia as the 116th Regiment, subsequently becoming part of the 29th Infantry Division. Though he planned to continue to command the regiment after the consolidation, Leedy failed rigorous physical tests and was relieved of command.