Miller was born March 6, 1993 to parents Robert and Sheila. He attended high school near his home town of Laytonsville, Maryland at Gaithersburg High School under coach Kevin Parrish. Miller was a captain during both his junior and senior seasons, averaging 13.1 points and 7.5 rebounds in his final prep year. He went on to play four years at Holy Cross and majored in philosophy. Miller has a brother and two sisters, and his sister Janell Thomas played college basketball at North Carolina Central. You can follow Miller on Twitter @MalcMili13 and on Instagram @mlmili13. Miller played four seasons at Holy Cross of the Patriot League, appearing in a total of 112 games (93 starts). Working at small and power forward, Miller improved his numbers each season with the Crusaders. By his sophomore season, Miller was a full-time starter. In his junior year, the 6-7 Miller was fifth in the Patriot League in total rebounds (195). He was also second in the Patriot leagues in total blocks in both his junior and senior seasons, and ranks 17th all-time on the conference block list. Miller had a career-best 14.5 ppg during his senior year, which was good for eighth in the Patriot League. Miller was not selected in the 2015 NBA draft, but spent several seasons between the D League and Germany before catching on with Toronto.