Felix Silla was born in a small village outside Rome, Italy. Silla trained as a circus performer, came to the United States in 1955, and toured with the Ringling Bros. and Barnum & Bailey Circus. His multiple talents as a bareback rider, trapeze artist and tumbler brought him to Hollywood, where he became a stuntman, starting with the Gig Young-Shirley Jones vehicle, A Ticklish Affair. His best-known roles are Litvak, the maniacal, miniature Hitler who menaces George Segal in The Black Bird (his favorite role), and Cousin Itt on the TV show, The Addams Family. He was also responsible for the physical performance of the robot Twiki in the TV series Buck Rogers in the 25th Century, a role for which the voice was supplied by Mel Blanc or Bob Elyea. In part due to his short stature of 1.19 m (3 ft 11 in), he has often doubled for children in such movies as The Towering Inferno, The Hindenburg, and Battlestar Galactica. Between movies, he frequently appears in Las Vegas and Reno night clubs with his own musical combo, “The Original Harmonica Band”.
His most famous role was television’s “Cousin Itt” of The Addams Family. Although the character of Cousin Itt did not debut on The Addams Family until almost a third of the way through the entire series, Silla’s performance of the character made him so popular that Cousin Itt was carried over into both the animated series and the motion picture versions of The Addams Family. He provided the voice of Mortimer Goth from The Sims 2, the best-selling video game of 2005. He also played one of the Ewoks in the movie Return of the Jedi.