Eldon Dedini was born on June 29, 1921 in King City, California. He was the son of an Italian dairy farmer and bookkeeper, and of a schoolteacher. His love of cartoons dates from his early boyhood, as he pored over "comic books" his mother made for him from the Sunday paper's comic section.
He graduated from Salinas Junior College (now Hartnell College), where he took art classes. Acting on the advice of his art teacher, the noted watercolorist Leon Amyx, Dedini compensated for the cartooning gap in the art curriculum through practical experience, contributing cartoons gratis to the local newspaper, the Salinas Index Journal. He continued his art education in Los Angeles at the Chouinard Institute of Art, where many of the Disney Studio's animators trained and where he met another artist, Virginia Conroy, whom he married on 15 July 1944, just after they both graduated. They adopted a son, Giulio, in 1960.
Dedini died of cancer in Carmel, California in January 2006, at age 84.