Once a crook, "Eel" O'Brian became a hero when he gained his powers. Usually working solo, he nonetheless helped Batman against the Molder. He later became fed up with being a costumed crime fighter and being referred to as a joke and took on the guise of Kyle Morgan, an explorer. He sought the love of Ruby Ryder, a rich business woman whom no man could tame, and they were engaged to be married. However, when O'Brian spurned her she hired Batman to bring him back home and had him shot. Plas faked his death, and Ryder was given the death penalty. However, Batman revealed the hoax, exposing Plas's true identity.
After this first team-up, Plastic Man teamed-up with Batman on a few more cases. He aided Batman again when thieves stole a department store Christmas display and they eventually worked with Metamorpho to stop Ruby Ryder; who manipulated Plastic Man for her own interests.
- This version of Eel O'Brian (Earth-One), including all history and corresponding appearances, was initially erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. However the ending of Convergence retroactively prevented that collapse, saving all the alternate realities, though in an "evolved" form. Even though versions of the character may have since appeared, this information does not apply to those versions.
- Robby Reed, the owner of the original Hero Dial, transformed into a version of Plastic Man on two occasions without explanation; on the second occasion, corrosion in the Dial caused Robby to become mentally unbalanced and attack the real Plastic Man, who defeated Robby and apparently confiscated the Dial. It was later seen back in Robby's possession.
- Appearances of Eel O'Brian (Earth-One)
- Images featuring Eel O'Brian (Earth-One)
- Quotations by or about Eel O'Brian (Earth-One)
- Character Gallery: Eel O'Brian (Earth-One)