The original Clayface, Basil Karlo, appeared in Detective Comics #40. He is a B-list actor who is driven insane when he hears that a remake of the classic horror film he had starred in, Dread Castle, would be shot without him acting in the film, even though he is to be one of the advising staff. Donning the costume of Clayface, a villain he once played in a different movie, he begins killing the actors playing characters he killed in the order and way they die in the film, along with someone who knew his identity. Last, he plans to murder the actor playing the Clayface killer. He is foiled by Batman and Robin.^[3]

He reappears after the prison ambulance he is riding in plunges off a cliff. He once again dons the mask of Clayface and targets Bruce Wayne's fiancée, Julie Madison. Once again, the Dynamic Duo foil his plans. A movie buff, Batman creator Bob Kane states that the character was partially inspired by the Lon Chaney, Sr. version of The Phantom of the Opera and that the name of the character comes from Boris Karloff and Basil Rathbone.^[4][5]

Much later, Karlo languishes in a prison hospital, when the current Clayface Sondra Fuller visits him out of curiosity. Karlo proposes an alliance between all living Clayfaces to kill Batman. He even arranged for a small piece of the remains of Matt Hagen to be gathered to make him a post-mortem member of the "Mud Pack", as the group called itself. Even though the "Mud Pack" is defeated, Karlo injects himself with blood samples from Preston Payne and Sondra Fuller, gaining the abilities to shapeshift and melt with a touch; he becomes the self-declared "Ultimate" Clayface.^[6] He is defeated by the combined efforts of Batman and Looker of the Outsiders by overloading his abilities, making him melt into the ground. He literally sinks into the Earth's crust when he loses control of his powers; he survives, however, and now his body sports crystals similar to quartz that endow him with greater powers. Karlo escapes his underground prison when Gotham City is struck by a great cataclysm. He captures Batman and is about to kill him, but he gets into a feud with Mr. Freeze about who has a right to kill the Caped Crusader. Using that distraction, Batman soundly defeats both of them.

During the "No Man's Land" storyline, Karlo holds Poison Ivy, who is in charge of producing fresh vegetables for the remaining people in the city, prisoner in Robinson Park. After she is freed from her prison by Batman, Poison Ivy battles and defeats Karlo, sinking him deep into the ground. It appears that the Ultimate Clayface is destroyed in this battle, but has resurfaced as a member of the Secret Society of Super Villains. Later, he seeks to increase his already formidable powers by absorbing Wonder Woman (a clay construct similar to him), giving him an amount of powers that bordered on invulnerability. While he is successful in absorbing some of the heroine's powers, causing her to regress to a teenage appearance resembling Donna Troy, he is ultimately returned to normal when Wonder Woman and Donna were able to trick Clayface into entering a train carriage with Wonder Woman while she was disguised as Donna, Donna subsequently using the Lasso of Truth to swing the carriage around and turn it into a mystical centrifuge, causing the clay Clayface had taken from Wonder Woman to split away from him and re-merge with Wonder Woman due to the differences between the two types of clay.

Basil Karlo is among the members of the Injustice League and is among the villains seen in Salvation Run. He can be seen as a member of Libra's Secret Society of Super Villains. In the second issue of Final Crisis, he triggers an explosion at the Daily Planet under Libra's orders when Lex Luthor demands for Libra to do something that will draw Superman to them.^[7]

Black Mask attempted to control Clayface by implanting a device in his body. He escaped Black Mask but was captured and imprisoned by the Outsiders.

In The New 52 (a reboot of the DC Comics universe) as a part of "Death of the Family" storyline, Poison Ivy breaks Basil Karlo out of Arkham intent on marrying him.^[8] This turns out to be a ruse with Poison Ivy messing with Karlo's mind. He later sets out to seek revenge.^[9]

Karlo later returns with a new plan: to use his DNA-duplication abilities to impersonate Bruce Wayne and take control of Wayne Enterprises. He even guesses that Wayne is Batman's true identity. However, Batman plants false evidence to suggest that he anticipated Karlo's attempt to take his DNA and tricked him into taking a fake sample. Batman eventually stops Karlo by trapping him in a security system that can only be deactivated with Karlo's original DNA, reasoning that he has changed too much for his original DNA to be present in his system.^[10]

In Detective Comics #934 (August 2016), Basil Karlo is recruited by Batman to join his new team of heroes to defend Gotham City from a new menace. This issue presents Karlo as more of a sympathetic character than seen in the past. Karlo accepts the offer to join Batman's new team.^[11]