Among many television credits, Romero appeared several times on The Martha Raye Show in the mid-1950s. He portrayed Don Diego de la Vega's uncle in a number of Season 2 Zorro episodes.  In 1958, he guest-starred as Ramon Valdez, a South American businessman, who excels at dancing the Cha-Cha with Barbara Eden in her syndicated romantic comedy, How to Marry a Millionaire in the episode entitled "The Big Order". He performed the mambo with Gisele MacKenzie on her NBC variety show, The Gisele MacKenzie Show. He guest-starred in 1957 on CBS's The Lucy-Desi Comedy Hour on the first episode of the seventh season ("Lucy Takes a Cruise to Havana"). He played "Don Carlos", a card shark on the episode, "The Honorable Don Charlie Story" of NBC's Wagon Train. On January 16, 1958, he appeared on The Ford Show, Starring Tennessee Ernie Ford. In 1959, Romero was cast as Joaquin in the episode "Caballero" from The Texan.  In 1960, he was cast as Ricky Valenti in "Crime of Passion" from Pete and Gladys. In 1965, Romero played the head of THRUSH in France in "The Never Never Affair" from The Man from U.N.C.L.E. From 1966 to 1968, he portrayed the Joker on Batman. He refused to shave his moustache for the role, and so the supervillain's white face makeup was simply smeared over it throughout the series' run and in the 1966 film.  His guest star work in the 1970s included was a recurring role on the western comedy Alias Smith and Jones as Senor Armendariz, a Mexican rancher feuding with Patrick McCreedy (Burl Ives), the owner of a ranch on the opposite side of the border. He appeared in three episodes. Romero later portrayed Peter Stavros on Falcon Crest (from 1985-1987). He also appeared in a sixth-season episode of The Golden Girls, where he played a suitor named Tony Delvecchio for Sophia. Apart from these television roles, Romero appeared as A.J. Arno, a small-time criminal who continually opposes Dexter Riley (played by Kurt Russell) and his schoolmates of Medfield College in a series of films by Walt Disney Productions in the 1970s.

Answer this question "Who is Cesar Romero?" by extracting the answer from the text above.
He portrayed Don Diego de la Vega's uncle in a number of Season 2 Zorro episodes.