Gerard was hired to get children involved with the show. He would interact with kids on location, and create a link with the show by playing a role in the street stories.
Previous attempts of child interaction (with the actors Annet van Heusden, Joyce Clements and Rudy Kühn) had failed: this concept proved to be successful, and other actors like Frank Groothof, Lot Lohr and Hakim Traïda still visit kids on location in recent seasons.
The low-budget location scenes with Gerard were shown the most between 1982 and 1984; Gerard was featured on the show until 1987.
On Television he played in seven years only two roles. Besides serving as Gerard Sesame Street, he played mr Reinders in the movie De Bende van Hiernaast. In which also Lex Goudsmit played a major role. Kuster also performed with Triola and as a street musician. He repeatedly took part in the Leiden street festival. He was nicknamed Ukulele Ike.