Miller attended Gaithersburg High School where he served as team captain during both his junior and senior seasons, averaging 13.1 points, 7.5 rebounds, 2.8 assists, 2.6 blocks and 1.4 steals per game as a senior, earning him first team All-Gazette honors and being ranked as one of the top 500 seniors in the nation by HoopScoop.
He played college basketball for Holy Cross. In four years at Holy Cross, Miller totalled 1,013 points, 532 rebounds, 164 assists, 143 blocked shots and 93 steals ranking third all-time in career blocked shots and sixth in career games started (93). As a senior, Miller averaged 14.5 points, 4.9 rebounds, 1.6 blocked shots, 1.3 steals and 1.2 assists per game for the Crusaders, while connecting on 37.2 percent of his three-point field goal attempts (45 of 121) and 83.0 percent of his free throws (117 of 141).
He finished the season ranked second in the Patriot League in blocked shots, fourth in free throw percentage, seventh in steals, eighth in scoring, 14th in three-point field goals made and 15th in rebounding.
Miller led the team in scoring 13 times and in rebounding 13 times that year, while scoring in double-figures 25 times. After going undrafted on the 2015 National Basketball Association draft, Miller joined the Boston Celtics for the 2015 National Basketball Association Summer League where he averaged 4.0 points and 1.3 rebounds in 12.1 minutes per game.
On September 25, 2015, he signed with the Celtics. However, he was later waived by the Celtics on October 20 after appearing in one preseason game.
On October 31, he was acquired by the Maine Red Claws of the National Basketball Association Development League as an affiliate player of the Celtics.
