Sergeant Major Christino is a native of Harrisburg, Pennsylvania. He enlisted in the Marine Corps in November 2001 and completed Recruit Training at Marine Corps Recruit Depot Parris Island, South Carolina, in February 2002. Upon completion of Recruit Training and Marine Combat Training, he attended Aviation Technician Common Core at Naval Air Station Pensacola, Florida, where he was promoted to Private First Class and subsequently meritoriously promoted to Lance Corporal. He then attended Intermediate Level Avionics Training at Marine Corps Air Station Cherry Point, North Carolina, earning the 6483 Military Occupational Specialty (MOS).
In 2003, Lance Corporal Christino reported to Marine Aviation Logistics Squadron 26, Marine Corps Air Station New River, North Carolina, as an Intermediate Level Avionics Marine. In 2004, he deployed for eight months with HMM-266 (REIN) aboard the USS Wasp and at Kandahar Air Base, Afghanistan, in support of Operation Mountain Storm. During the deployment, he worked directly with the Afghan military in support of Kandahar Air Base operations and was promoted to Corporal. In November 2004, Corporal Christino reported to Marine Aviation Logistics Squadron 29, where he served as a Work Center Supervisor. He was promoted to Sergeant in September 2006 and earned his Collateral Duty Inspector qualification.
In June 2007, Sergeant Christino reported to Marine Aviation Training Support Group 21, Naval Air Station Pensacola, Florida, where he served as an Avionics Instructor. He earned his Martial Arts Instructor, First Degree Black Belt, through the Marine Corps Martial Arts Program and was responsible for the MCMAP belt upgrades of more than 400 Marines. In April 2009, Sergeant Christino was named Honor Graduate of Staff Noncommissioned Officer Academy Class 4-09 at Camp Johnson.
In June 2010, Sergeant Christino reported to Marine Aviation Logistics Squadron 36, Okinawa, Japan, where he served as Assistant SNCOIC of the Communications and Navigation Work Center. In August 2011, he attended the Martial Arts Instructor Trainer Course in Quantico, Virginia, and was recognized as a Distinguished Graduate upon completion. He was meritoriously promoted to Staff Sergeant in April 2012 and assumed the duties of Operations Chief at Marine Aircraft Group 29. In April 2013, Staff Sergeant Christino was selected as Honor Graduate and recipient of the Director's Physical Fitness Award for SNCOA Career Course Class 4-13.
Staff Sergeant Christino reported to Marine Aviation Logistics Squadron 29 in July 2013, where he served as a Work Center Supervisor and earned his Collateral Duty/Quality Assurance Representative qualification. In October 2015, he reported to the Staff Noncommissioned Officer Academy at Camp Lejeune, North Carolina, where he served as a Faculty Advisor. He was promoted to Gunnery Sergeant on 1 November 2016. In May 2017, Gunnery Sergeant Christino assumed the duties of Sergeants Course Chief Faculty Advisor and, in October 2017, became the Sergeants Course SNCOIC.
In February 2019, Gunnery Sergeant Christino reported to Marine Aviation Training Support Group 23, Aviation Maintenance Squadron 2, where he served as the Squadron Gunnery Sergeant. He was promoted to First Sergeant on 1 June 2020 and assumed the duties of the AMS-1 Squadron Senior Enlisted Leader.
In June 2022, First Sergeant Christino assumed the duties of Echo Battery Senior Enlisted Leader, 2d Battalion, 10th Marine Regiment. In February 2023, he assumed the duties of Headquarters Battery Senior Enlisted Leader. On 30 May 2024, First Sergeant Christino was promoted to his current rank of Sergeant Major and assumed the duties of the HMHT-302 Command Senior Enlisted Leader.
Sergeant Major Christino's personal awards include the Meritorious Service Medal with one gold star in lieu of second award, the Navy and Marine Corps Commendation Medal with one gold star in lieu of second award, the Navy and Marine Corps Achievement Medal with two gold stars in lieu of third award, and the Military Outstanding Volunteer Service Medal.