(written from a Production point of view)
Oscar Katz (12 April 1913 – 3 January 1996; age 82) was a television producer, who was the head of production at Desilu between 1964 and 1965. Previously, he worked as a television executive in New York City, serving among others, as Vice President of Network Programs at CBS.
Katz was hired by Lucille Ball to oversee the developement and production of Desilu's programs in 1964. His main task was to find writers/producers with new ideas, and develop them into successful television pilots. Katz, who was very unexperienced with West Coast studio production and business, soon hired Herb Solow as his assistant. Together, they helped to bring Gene Roddenberry's Star Trek and Bruce Geller's Mission: Impossible to life. He served as Executive in Charge of Production on the two pilots, "The Cage" and "Where No Man Has Gone Before". However, in early-1966, Katz left Desilu. Solow succeeded him in his position, and remained there until the studio was merged with Paramount Pictures.
Marc Cushman's reference book, These Are the Voyages: TOS Season One suggests that Katz left Desilu as a result of the warfare between Lucille Ball, Solow and the "old guard" executives, who thought that such expensive productions as Star Trek and Mission: Impossible would bankrupt the studio, and Katz was their main culprit.
After he left Desilu, Katz retired from the television business and became a securities analyst and stock market investor. He died of pneumonia in Los Angeles, California. (Inside Star Trek: The Real Story, pp 6-11, 441)