Main Source, Large Professor soon after became a full-time producer working with such acts as Big Daddy Kane and A Tribe Called Quest. Professor originally became involved in rap when he won a tryout held by Main Source members K-Cut and Sir Scratch in 1989. Contributing significantly to the creative direction of the group, Professor eventually broke with Main Source over creative differences. He then lent his hand to albums by some of rap's biggest names, including Eric B. & Rakim, Nas, and Pete Rock & C.L. Smooth. For his full-length solo debut, 2002's 1st Class, Large Professor called in favors from friends including Nas, Q-Tip, and Busta Rhymes. 2008's Main Source featured Big Noyd, AZ, and Styles P.