Major Calvin enlisted in the Marine Corps in August of 1996. After graduating Recruit Training from MCRD San Diego, Major Calvin proceeded to the School of Infantry completing the basic rifleman package (0311), and follow on training as a Light Armored Reconnaissance crewman (0313). Upon graduating from MOS School in March of 1997, Major Calvin checked into 4th Light Armor Reconnaissance Battalion Headquarter & Support Company, Camp Pendleton.
Major Calvin served as a driver and vehicle commander from April 97 to 2000 and was meritoriously promoted to Corporal in 2000, in January 2001, he transferred to Delta Company 4th LAR and assumed the role of Driver and Gunner until October 2001. In Oct 2001, he reported to OCS, and was commissioned in December 2001.
Maj Calvin attended The Basic School in Jan. 2002 and the Infantry Officer Course, graduating in Feb 2003. Upon completing IOC, Maj Calvin reported to I MEF as the OIC of a rifle security company and deployed in support of Operation IRAQI FREEDOM I in March 2003. Major Calvin completed his assignment in May of 2003 and subsequently reported to 3d Battalion 1st Marines. In July 2003 Major Calvin detached from 3/1 and reported to MARFORSOUTH, for augmentation to 7th Group (SF) for duty in Colombia, conducting counter insurgency operations and completing the Colombian Lancero Course. Upon completing his assignment, he reported back to 3/1 and was assigned as a Weapons Platoon Commander for Lima Co. Major Calvin redeployed in support of OIF 2 in June of 2004 where he participated in operation AL FAJR, In 2005 he deployed with 3/1 as the Weapons Company XO to Haditha Iraq for OIF rotation 06-04.2.
Major Calvin reported to the School of Infantry (W) in June of 2006 where he served as the Scout Sniper and Squad Leaders Course OIC and operations officer for Advanced Infantry Training Company and the S-3 for SOI. In July of 2008 Major Calvin attended Expeditionary Warfare School.
After augmenting the OCS staff in the summer of 2009, Major Calvin took command of Weapons Company 3/7 deploying in 2010 in support of operation ENDURING FREEDOM to Sangin, Afghanistan. Upon completing his deployment Major Calvin was assigned as the plans officer for Advisor Training Group until 2013.
In September 2013 Major Calvin reported to 5th ANGLICO, Okinawa Japan, serving as a Brigade Platoon Commander and the Operations Officer. In 2016 Major Calvin was selected to attend the Command and General Staff Officers Course in Ft. Leavenworth Kansas. In July 2017, Maj Calvin reported to 1st LAR and assumed the role of Executive Officer.