With his partner Juan Luis Cano, Fesser created in 1984 Gomaespuma, a company that has produced shows and commercials for radio and television as well as books, music albums and cultural events.

This non profitable organization is mostly dedicated to facilitate an access to education to hundreds of children in Nicaragua and Sri Lanka.

For 25 years (1982–2007) he was hosting with his partner Juan Luis Cano one of the most popular radio shows in Spain: Gomaespuma.

During the Gomaespuma years, Cano and Fesser traveled around the world to cover the news, interviewing key people like the King of Jordan and Vice President Al Gore just to name a few.

Due to that experience, later he manipulated and gave his voice to the funny puppet that appeared in his brother first short film Aquel ritmillo [es].

He also worked as a script supervisor on El Secdleto de la Tlompeta [es], the multi-awarded second short film directed by Javier.

In the mid-1980s Guillermo Fesser presented the TV program La Tarde de Verano, with Pastora Vega and Toni Cantó, and for some months in 1992, the contest VIP Noche at Telecinco.

Accomplished by Javier Fesser and with scripts of Juan Luis Cano [es] and himself, the program was released in 1994 named Gomaespuma.

This book tells the story of Cándida Villar [es], the Fesser family housekeeper, a woman from Martos (Jaén).

It is the story of its beginnings as a housemaid, the mistreatment of her husband and her current life, working as film critic for Gomaespuma.

Guillermo Fesser has been lately involved with projects that support the ideas behind the Buy Local and Slow Food movements.

[4][12] He is working with writer Mark Burns on a film about sustainable farming and the dangers of natural gas hydraulic fracturing.