Gillespie was a vocal fixture in many of John Hubley and Faith Hubley’s animated films, such asThe Hole, The Hat, and Voyage to Next.
In the 1980s, Gillespie led the United Nation Orchestra. For three years Flora Purim toured with the Orchestra and she credits Gillespie with evolving her understanding of jazz after being in the field for over two decades. David Sánchez also toured with the group and was also greatly influenced by Gillespie. Both artists later were nominated for Grammy awards. Gillespie also had a guest appearance on The Cosby Show as well as Sesame Street and The Muppet Show.
In 1982, Gillespie had a cameo appearance on Stevie Wonder’s hit Do I Do. Gillespie’s tone gradually faded in the last years in life, and his performances often focused more on his protégés such as Arturo Sandoval and Jon Faddis; his good-humoured comedic routines became more and more a part of his live act.