The 20th Century Fox logo font was created by artist Emil Kosa, Jr. He painted the logo on layers of glass so that it could be animated. Over the years, the logo has been modified, such as when the lettering was changed from 20th Century Pictures to 20th Century Fox.
While the logo lettering wasn't created from any one font, it does bear some similarities to different fonts. Kosa's logo is done in an Art Deco style, so the font is similar to fonts used in other Art Deco graphics and artwork. These fonts are very simple. The font in the logo is similar to fonts such as Helvetica, Bernhard Fashion, and Blakely.