Barry O'Neill was a wealthy, independent, playboy adventurer. For several years in the 1930s, alongside Inspector Le Grand of the French Intelligence Office, O'Neill and a few allies fought a long-running campaign against a Chinese cult-leader, alchemist, terrorist, and warlord called Fang Gow, the "inscrutable and vengeful enemy of the Human Race."
- This version of Barry O'Neill, 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.
- Some time before More Fun Comics #7, O'Neill's black hair turned red.
- Appearances of Barry O'Neill (Earth-Two)
- Images featuring Barry O'Neill (Earth-Two)
- Quotations by or about Barry O'Neill (Earth-Two)
- Character Gallery: Barry O'Neill (Earth-Two)