Eiso Jan Gerhard Toonder is the oldest son of Marten Toonder and Phiny Dick. During his school holidays he had apprenticeships with his father's Toonder Studios. He was a copywriter for advertising agencies until 1961, when he moved to Ireland. There, he set up Toonder Film Ltd., and specialized in TV spots.
After a couple of years, he took up scriptwriting for several comics from his father's studios, such as the daily 'Kappie', 'Panda' and 'Koning Hollewijn' strips, and some 'Tom Poes en heer Bommel' stories for Donald Duck. He and his father also developed a new comic, called 'De Goeroe' in the 1970s. It ran for about ten years in De Telegraaf and for three more years in The Irish Times. The strip appeared under the penname of Peter Abel, and there are rumours that there was also an Irish artist called Peter Hoye involved. Later, it appeared that Hoye never existed, and that 'De Goeroe' was compiled by Eiso himself from drawings made by Marten Toonder and Piet Wijn.
Eiso Toonder claimed to have contributed lay-outs and pencils to the 'Tom Poes' daily strips 'Tom Poes en de pijpleider', 'Heer Bommel en de minionen' (partially), 'Heer Bommel en het ontsollen' and 'Heer Bommel en de spalt', filling in for Piet Wijn. Eiso Toonder has always been involved in his parents' work, organizing archives, overseeing and writting prefaces to reprint collections and giving lectures.