Having earned the nickname “The Man of a Thousand Voices,” Blanc is regarded as one of the most influential people in the voice-acting industry. Although he began his nearly six-decade-long career performing in radio commercials, Blanc is best remembered for his work with Warner Bros. during the Golden Age of American animation (and later for Hanna-Barbera television productions) as the voice of such well-known characters as Bugs Bunny, Daffy Duck, Porky Pig, Sylvester the Cat, Tweety Bird, Foghorn Leghorn, Yosemite Sam, Wile E. Coyote, Woody Woodpecker, Barney Rubble, Mr. Spacely, Speed Buggy, Captain Caveman, Heathcliff, Speedy Gonzales and hundreds of others.
Blanc was interested in music at an early age and became proficient on bass, violin, and sousaphone. He began his professional life as a radio musician in the late 1920s, and in 1933 he and his wife cohosted a daily radio program from Portland, Oregon. As the low-budgeted show did not allow for the hiring of supporting actors on a daily basis, Blanc was compelled to provide a variety of voices himself and thus began honing the skills that brought him success.
He did freelance work for Los Angeles-area radio stations throughout the 1930s and in 1937 joined Leon Schlesinger's animation unit at Warner Bros. studios. Nicknamed “Termite Terrace” because of its spartan accommodations on the Warner lot, Schlesinger's unit produced the enormously popular and enduringly influential Looney Tunes and Merrie Melodies cartoon shorts. Blanc's first assignment for the company was to give voice to a drunken bull in the 1937 short Picador Porky.