Sam Tanner was one of several men forced by Peter Silverstone to become Blackrock.
Samuel Tanner was the President of the United Broadcasting Company. Convinced that his network was second in the ratings because his chief competitor, Galaxy Broadcasting, had so many exclusive stories concerning Superman, Tanner ordered his chief research scientist, Dr. Peter Silverstone, to create a superhero for UBC to exploit. Silverstone created a costume and called this new superhero Blackrock. However, Silverstone chose Tanner as the wearer of the Blackrock supersuit, in which Tanner was hypnotized by Silverstone without his knowledge into becoming his own superhero. Tanner fiercely competed against Superman while remaining ignorant that his "heroic" acts only place people in danger. Ultimately, Superman discovered Tanner's identity and defeated him. Tanner returned to normal with no knowledge of his alter-ego.
- This version of Blackrock, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 6 Appearances of Samuel Tanner (Earth-One)
- 2 Images featuring Samuel Tanner (Earth-One)
- 1 Quotations by or about Samuel Tanner (Earth-One)
- Character Gallery: Samuel Tanner (Earth-One)