COL Flaherty began his military career in 1966 with an enlistment in the US Army. He completed Basic Training at Fort Ord, California and Advanced Individual Training as a medic (91B) at Fort Sam Houston, Texas. He was then selected for the Army’s second 91C course and trained in Madigan Hospital at Fort Lewis, Washington. Following this 91C training, he deployed overseas as a medic serving with the 4th Bn, 144th Artillery and the 2nd Bn, 23rd Infantry including combat action on the Demilitarized Zone. He also served overseas with the 2nd Bn, 9th Mechanized Infantry and the 2nd Infantry Division.

COL Flaherty was commissioned in 1972. While on active duty as an Army Nurse, he served in the Burn Unit, Brook Army Medical Center then trained at Walter Reed Army Medical Center in the Mental Health Clinical Specialist course. Following this training, COL Flaherty served at Fort Bliss, Texas in the outpatient psychiatric department, as OIC for the inpatient psychiatric unit then as Commandant for the Army’s first psychiatric day hospital. COL Flaherty’s final active duty assignment was AMMED Liaison Officer for the 3rd Armored Cavalry, Fort Bliss Texas.

COL Flaherty joined the National Guard in 1980 and was assigned to the 143rd Evacuation Hospital in Los Alamitos, California. COL Flaherty served as Chief Nurse of the 143rd Evacuation Hospital from 1982 until its deactivation in 1997. COL Flaherty supervised 143rd nursing personnel for Team Spirit Korea (1983 & 1989) and Wounded Warrior (1985, 1988 & 1992) exercises and support to the LA Olympics in 1984, the Forks of the Salmon Fires in 1987, the San Francisco Earthquake in 1988, the LA Riots in 1992, the Northridge Earthquake in 1994 and the Nuevos Horizantes humanitarian mission to Panama in 1996. COL Flaherty was also deployed to Panama in 1985 as Medical Site Commander in support of the Alabama National Guard.