Gerardo studied at the University of Science and Arts of Oklahoma in Chickasha, Oklahoma, United States. In 1999 he became a Bachelor.
Gerardo worked as an editorial cartoonist of the Diario Extra in San Jose, Costa Rica from 1980 to 1982. In 1981 he became a director of the art department of the Sam Advertising Agency. He worked there for a year. Since 1983 he was an editorial cartoonist in Tico Times in San Jose, Costa Rica. From 1986 to 2001 Gerardo worked as an editorial cartoonist in Tico Times in San Jose, Costa Rica. Since 1986 he worked as a professor of art at the University of Costa Cira. In a year he became an editorial cartoonist of the Cartoonist and Writers Syndicate in New York City, United States. In 1993 he worked in La Prensa in Panama. From 1994 to 1996 he was a cartoonist in El Nuevo Herald in Miami, Florida, United States. In 2000 he worked in Courrier International in Paris, France. Since 2001 he was a producer at Canal 13 in San Jose, Costa Rica.
Gerardo married to Noemy Montoya on May 20, 1988. Children: Jonathan, Adam, Melissa.