The president of the United Broadcasting Corporation.
For a brief time, Tanner secretly becomes the villain Blackrock (Act No. 458/1, Apr 1976: "Make me a Super-Hero!"; Act No. 459/1, May 1976: "Superman's Big Crack-Up!").
Among Tanner's known relatives is his nephew, the comedian Les Vegas (S No. 315, Sep 1977: "Good Evening Superman --I'm Clark Kent ... and You're Not!").