Command Sgt. Maj. Thomas O. Calarco assumed duties as Command Sergeant Major of U.S. Army Garrison, Fort McCoy, Wis., on July 13, 2023.  Immediately prior to this assignment, he served as the Unites States Army Reserve Command Surgeon Directorate Sergeant Major, at Fort Liberty, NC.

He is a graduate of Upper Iowa University with a baccalaureate degree in psychology and the Finger Lakes Community College with an associate in applied science. His military education includes Sergeants Major Course Class 68, Distribution Learning Course (DLC) Level 5, Senior Enlisted Joint Professional Military Education (SEJPME) I&II, Foundation Training Developer, Master Resilience Training, Master Leader Course, Intermediate Facilitation Skills, Foundation Instructor Facilitator, Small Group Leader Course, Basic Instructor Course, Army Training Requirements and Resource Systems (ATRRS), Quota Managers Course, Unit Mobilization Planners Course (UMPC), Physical Security course, Anti-Terrorism I&II, Operations Security (OPSEC) I&II, First Sergeant Course, 68W Advance Non-Commissioned Course (ANCOC), US Army Recruiting Course, Battle Staff, 68W Basic Non-commissioned Officer Course (BNCOC), Primary Leadership Development Course (PLDC), 68W Health Care Specialist, 68D Operating Room Specialist, and Basic Training.   

His previous assignments include Operations Sergeant Major at 8th MED BDE; Master Leader Course Instructor/Course Manager at 83rd USARRTC: UMPC Instructor/Course Manager at 83rd USARRTC; ATRRS Instructor/Course Manager at 83rd USARRTC; Intelligence Noncommissioned Officer In Charge at 8th MED BDE; AGR First Sergeant for the 3274th United States Army Hospital (USAH); AGR First Sergeant for Task Force Medical KFOR 15; Emergency Operations Noncommissioned Officer In Charge at ARMEDCOM; Detachment NCO 338th Minimum Care Detachment; US ARMY Recruiter for Dubois Recruiting station; Training NCO at ARMEDCOM; and Training NCO at 330th Combat Support Hospital.

He deployed with the 3274th USAH Task Force Medical KFOR 15 to Kosovo in 2011.

His awards and decorations include Meritorious Service Medal (5th award), Army Commendation Medal (4th award), Army Achievement Medal (2nd award), National Defense Service Medal (2nd award), Global War on Terrorism Service Medal, Kosovo Campaign Medal, Noncommissioned Officer Professional Development Ribbon with Number 5, Army Serve Ribbon, Overseas Service Ribbon, Meritorious Unit Citation, the Recruiter Gold Badge, and Instructor Badge.