He and his friend Alonzo Brown formed the rap duo Dr. Jeckyll and Mr. Hyde while in high school, which became known for the songs "Genius Rap," "Fast Life," and "AM/PM."
He attended Lehman College with the intentions of becoming a newscaster, but later dropped out and started working in radio.
He has been married to acclaimed choreographer Laurieann Gibson. He has a son named Gianni.
He met Russell Simmons in 1983 and got a job at Simmons' Rush Communications. Harrell eventually became vice president of the company.