Gilmore is the grandson of Roy Haynes, who gave him his first drum kit at the age of ten. A graduate of the Fiorello H. LaGuardia High School of Music & Art and Performing Arts, he has also received several awards such as the Wynton Kelly Foundation Award and the Wyoming Seminary PAI Best Instrumentalist Award. Marcus has been named a protégé of the 2018 Rolex Mentors And Protégé project.