Major Byrnes was born in Bronx, New York on 15 October 1973. He attended the State University of New York at Buffalo and received his BS in Criminology in 1995. He received his commission on 10 December, 1998 following graduation from Officer Candidate School. Second Lieutenant Byrnes reported to The Basic School in January 1999 and joined Bravo Company, Basic Officer Class (BOC) 2-99. Following The Basic School, he was assigned to Naval Air Station Pensacola, Florida and was designated a Naval Aviator in July 2001. He attended Survival, Evasion, Resistance and Escape (SERE) School in Warner Springs, CA prior to reporting to Marine Corps Air Station (MCAS) Camp Pendleton, California for initial training in the UH-1N in September, 2001.
His first fleet assignment was with Marine Light Attack Helicopter Squadron (HMLA) 367 from February 2002 to January 2006. During this tour, he deployed to Okinawa, Japan for 13 months as part of the Unit Deployment Program (UDP). Midway through this deployment he attached to Marine Medium Helicopter Squadron (HMM) 262 as part of the 31st Marine Expeditionary Unit (MEU). In September of 2004, he deployed to Iraq in support of Operation Iraqi Freedom (OIF) 2-2 where his unit supported operations out of Al Taquadum Air Field. During his time with HMLA-367, Captain Byrnes served in various billets in the Logistics, Operations, Safety and Maintenance Departments.
In February 2006, Captain Byrnes deployed with the 3rd Marine Aircraft Wing (3D MAW) as a Rotary Wing Fragger in support of Operation Iraqi Freedom (OIF) 5-7.
Captain Byrnes reported for duty as an instructor at Marine Light Attack Helicopter Training Squadron (HMLA/T) 303, Camp Pendleton, California in September 2006. During his three years at HMLA/T-303 he served as Pilot Training Officer, Assistant Operations Officer, NATOPS Model Manager and Administration Officer in Charge (OIC). Major Byrnes was promoted to his current rank on 1 February 2009.
In September 2009, Major Byrnes reported to Marine Corps Air Facility, Quantico, where he served as the Assistant Operations Officer and augmented Officer Candidate School where he served as a Company Commander for Officer Candidate Class 204.
In August 2011, Major Byrnes reported to Marine Aircraft Group (MAG) 29 and deployed directly to Afghanistan in support of Operation Enduring Freedom (OEF), where he served as a Future Operations Planner. Upon returning from Afghanistan, Major Byrnes reported to HMLA-467 where he served as the Assistant Maintenance Officer and Executive Officer. In February 2015 Major Byrnes was assigned to Marine Wing Headquarters Squadron Two.
His personal decorations include the Air Medal with Strike/Flight Numeral "8" and the Navy and Marine Corps Commendation Medal with Gold Star.