Jaffe's career was mainly based on doing voice-over work. She is best remembered as the voice of the nerdy-and-intelectual Velma Dinkley in the Scooby-Doo cartoons from 1969-1973; before actress Pat Stevens picked up the role. After the demise of the last Scooby cartoon Scooby-Doo!: Yeni Bölümler (1972) (in 1973), Jaffe got married and left Hanna-Barbera Studios, only to become a agent for actors/actresses at William Morris Agency - a year later; in 1974. Since 1974, Jaffe (now going by Nichole David) is still an agent, and at the same company.

Some of Jaffe's other movie roles include Betty Smith, the girl who was seductively trying to land Elvis Presley in The Trouble with Girls (1969) and as the hippie girl in the dune-buggy in Disney's Aşk Böceği (1969).