After Mac enjoyed a big year in 2011 when his album, “Blue Slide Park,”debuted at Number 1 on the Billboard 200 chart. Mac Miller continued his upward trajectory in 2012. Mac just finished the Under the Influence Tour with Wiz Khalifa, and recently Mac Miller embarked on the second leg of ‘The Macadelic Tour’ in support of his 2012 “Macadelic” mixtape. While rocking major crowds, Mac is finishing up two projects at the same time: his collaborative album “Pink Slime” with Pharrell Williams. And his solo follow up to “Blue Slide Park.” In short, Mac Miller’s final year on our 21 Under 21 list was a very success one.