Education
Mack played high school basketball at Paterson Catholic High School for his first three seasons. During his junior season, he helped Paterson Catholic achieve a 28-1 record and at one point the number 3 rank in the national polls. He scored a total of 979 points there.
The school then closed after the 2010 academic school year, leading Mack to transfer to well-renowned located in Jersey City and play under head coach Bob Hurley.
Mack achieved great success with Saint Anthony during his senior season in 2011 as well, leading the team to a perfect record of 33–0 and the #1 national ranking according to United States of America Today.
They eventually went on to win a state title. He averaged 15.2 points, 3.6 assists and 2.9 steals per game as a senior helping him achieve national recognition.
Mack was nationally ranked 112 overall and 22 as a point guard in the class of 2011 according to Rivals.com while ranking 63rd overall according to ESPNU Top 100. On September 1, 2010, Mack officially committed to play for the Scarlet Knights.