American character actor in scores of films after substantial stage experience. He was born in DeSoto, Missouri, but raised in Atchison, Kansas. The son of a railroad worker and law clerk (some publicity material states the father was a physician, but family and census records show otherwise), he wavered between various careers including oil exploration, but found his way after an introduction to the stage with the Atchison Civic Theatre and Kansas City Civic Theatre. He briefly attended the University of Kansas (where he was a fraternity brother of future newsman John Cameron Swayze ). He moved from Kansas to California in 1930, where he lived with his grandparents and worked in the lemon groves near Pomona prior to opening a tire-repair shop in that city. He also helped found a theatre company in Pomona. He joined the Pasadena Community Playhouse, where he was spotted by a Warner Bros. talent scout looking for someone with a resemblance to Henry Clay, for the Warners short film The Monroe Doctrine (1939). He signed with Warners as a contract player and was thereafter virtually never without work. He played in an enormous number of films over the next three decades, mostly in small supporting roles. He was equally adept at playing businessmen, attorneys, or historical figures, and was a familiar face on screen and on television for his entire career, though most people would have been unable to identify him by name. Perhaps his greatest fame came in the TV role of oil company president John Brewster on "The Beverly Hillbillies" (1962). During the last years of his life, he was co-owner of a popular restaurant/bar in Encino, California, called The Oak Room. Wilcox died in 1974.

In the final release print of 1951's Show Boat (1951), Wilcox, as a poker player, had no lines -- unusual for a familiar supporting actor who usually had a speaking part. But his role may have been a little more substantial in the rough cut, because the scenes of Gaylord Ravenal and Magnolia's "winning streak" in Chicago were trimmed some after it was decided that they slowed down the film.Studied at the Pasadena Community Playhouse alongside George Reeves , who was among his closest friends. He was best man at Reeves's wedding and they appeared in eleven films together.Honorary mayor of Granada Hills, California during the 1960s.Served on the Screen Actors Guild Board of Directors.