Jacobs spent most of his childhood moving around the East Coast with his family, eventually settling in Tampa, Florida. As a drummer he won the 1978 “Most Talented” trophy at Greco Junior High School, but after relocating to Queens, New York (as a result of his parents’ divorce), he traded his drums in for a set of turntables upon discovering and marveling over hip hop while the art form was still in an underground developmental stage. He was mentored in the craft by his cousin Rene Negron (a.k.a. DJ-Stretch), and their close friend Shawn Trone (a.k.a. MC Shah-T of the parody-rap group No Face) who suggested Greg use the name “Shah-G”. Jacobs liked the idea, but mistakenly thought his friend said “Shock-G”, and began using that name instead.
Less than two years later, after returning to Tampa, he dropped out of Chamberlain High School to form the Master Blasters, a mobile deejay crew which featured three DJs and four emcees at its height. They performed at parties, and also for the crowds at Riverfront Park’s outdoor Sunday gatherings, eventually capturing the interest of Tony Stone, a program director at WTMP radio, which was the city’s primary R&B station. Tony offered Jacobs, who was sixteen at the time, a job deejaying on the air, and for a short while, as “Gregory Racker”, he was the youngest radio personality in central Florida with a regular time slot. After being fired for playing the fifteen-minute-long album version of “(Not Just) Knee Deep” by Funkadelic in a five-minute time slot, and also after tensions with his father escalated, Jacobs found himself backpacking the United States for a few years, drifting through odd jobs and petty criminal adventures. It was during this excursion that his focus switched from deejaying to keyboard playing, and while utilizing piano practice-rooms at music stores and colleges around the country, he effectively taught himself to play the piano.
Deciding to pursue music seriously, he returned home, quickly obtained a diploma, and began attending Hillsborough Community College, where he studied music theory under Jim Burge and piano under Patricia J. Trice. It was there at HCC that he met and formed a bond with Kenneth Waters, and the two began performing together under various names including The Chill Factor, and also The Four Horsemen, which included MC Skoobie-D, and the MD Dazzlin Doc-P who had recently moved to Tampa from the Bronx, hip hop’s birthplace. Then in 1985, after two years of producing local artists for hire, playing solo piano gigs around town, performing with Kenny, and being a keyboardist in Warren Allen Brooks’ band, Greg and his aspiring-actress girlfriend (Davita Watts) set their sights beyond Tampa, and eloped to Los Angeles in search of greater opportunity. There he played keyboards in Kenny McCloud’s pop-funk band “Onyx” before leaving LA and finally arriving in the San Francisco bay area where he found work in an Oakland music store, and where Digital Underground would happen a few years later.