Maj. Grant McCloskey is a native of Indiana. He graduated Wabash College in 2012 with a Bachelor of Arts degree while majoring in History. He attended Officer Candidates School in 2013. He commissioned in November of 2013 and graduated from The Basic School and Infantry Officers Course in 2014. In September 2014 he reported to 2nd Light Armored Reconnaissance Battalion.    
 
From October of 2014 to June 2017, Maj. Grant McCloskey served as an LAR Platoon Commander, Company Executive Officer, and Company Commander while assigned to 2nd Light Armored Reconnaissance Battalion. In 2016 he deployed with his Platoon in support of the Black Sea Rotational Force 16.1 as part of Battalion Landing Team 1/8.  
 
In June of 2017, Maj. Grant McCloskey reported to the Basic School where he would serve from 2017 to 2020. While assigned to the Basic School, he served as the Platoon Package Primary, Staff Platoon Commander for Delta Company 4-18, Company Executive Officer for the Warrant Officer Basic Course 1-19 and The Instructor Education Program. 
 
In 2020, Maj. Grant McCloskey attended the Expeditionary Warfare School in Quantico, VA. In June 2022 he reported to 1st Light Armored Reconnaissance Battalion, where he served as the Company Commander for Arthur Company. Maj. Grant McCloskey and Arthur Company deployed with Battalion Landing Team 2/4 on the 13th Marine Expeditionary Unit to the INDOPACOM AOR, participating in bi-lateral training exercises in Singapore, Indonesia, Thailand, and South Korea. Upon return from deployment, Maj. Grant McCloskey was assigned as the Operations Officer for 1st Light Armored Reconnaissance Battalion.  
 
In January 2024, Maj. Grant McCloskey was assigned to his current billet at RS Richmond.