Sergeant Major Christina A. Grantham, nee Morehead, was born in Iwakuni, Japan, and enlisted in the Marine Corps on November 10, 1997.  After graduating from Marine Recruit Depot Parris Island and completing Marine Combat Training, she reported to Marine Corps Communications Electronics School for training as an Aviation Radio Repairman.  Upon receiving the Military Occupational Specialty of 5937, she reported to Marine Air Support Squadron 2 at MCAS Futenma, where she served from April 1999 through April 2000.

In April 2000, Lance Corporal Morehead transferred to Marine Tactical Air Command Squadron 38, where she served in the Communications & Electronics Platoon until September 2002.  While there, Sergeant Morehead detached and augmented the 3d Marine Aircraft Wing (Forward) as the Communications Chief for Exercise INTERNAL LOOK in Kuwait.  The detachment served as the advanced party for the Tactical Air Command Center to support follow-on operations in Operation IRAQI FREEDOM.

In February 2003, Sergeant Morehead was selected for the Marine Security Guard Program. Upon completion of embassy watchstander training, she served at the American Embassies in Nicosia, Cyprus; Amman, Jordan; and Valletta, Malta. She completed Marine Security Guard duty in September 2005.

In October 2005, Sergeant Morehead transferred to Marine Air Support Squadron 3, her Military Occupational Specialty changing to 5939, Aviation Communications Systems Technician. While assigned there, she deployed in support of Operation IRAQI FREEDOM 5-7, from January 2006 through August 2006, operating the Direct Air Support Center from Fallujah, Iraq.

In January 2007, Staff Sergeant Morehead reported to the Marine Air Command and Control Squadron- Experimental, Operational Development Team located at the Marine Corps Tactical Systems Support Activity on Camp Pendleton, CA. While assigned there, she was responsible for the development and testing of the Common Aviation Command and Control System, focusing primarily on the AN/MRQ-13 communications system and the integration of the Composite Tracking Network.

In June 2010, Gunnery Sergeant Aultman (nee Morehead) was transferred to Marine Tactical Air Command Squadron 38 for duty as the Aviation Communications Chief. While assigned there, she deployed in support of Operation ENDURING FREEDOM 10.2, from September 2010 through March 2011, as the Tactical Air Command Center Detachment Staff Noncommissioned Officer in Charge. In February 2012, she again deployed in support of Operation ENDURING FREEDOM as the Marine Air Control Group 38 (Forward) S-6 Chief, returning in August 2012.

In June 2013, First Sergeant Aultman reported to 1st Supply Battalion on Camp Pendleton, CA. While assigned there, she served as the Company First Sergeant for Ammunition Company from July 2013 to May 2015, Supply Company from May 2015 to May 2016, and Headquarters & Service Company from May 2016 through September 2016.

In September 2016, First Sergeant Grantham reported to Combat Logistics Battalion 4 on Camp Foster, Okinawa, Japan. While assigned there, she served as the Company First Sergeant for Headquarters & Service Company from October 2016 to May 2017, and Transportation Services Company from May 2017 to January 2018.

In January 2018, Sergeant Major Grantham assumed her duties as the Squadron Sergeant Major of Marine Air Support Squadron 2 at MCAS Futenma, Okinawa, Japan.  In October of 2019, Sergeant Major Grantham reported to MCAS Miramar, California, where she currently serves as the Squadron Sergeant Major for Marine Aviation Logistics Squadron 11, the oldest squadron in the Marine Corps. 

Sergeant Major Grantham's personal awards include the Meritorious Service Medal with gold star in lieu of second award, the Navy and Marine Corps Commendation Medal with gold star in lieu of second award, and the Navy and Marine Corps Achievement Medal with two gold stars in lieu of third award. She has a Bachelor's of Science degree in Legal Studies from the University of Maryland University College.