- You!? The masked man who keeps following me!
- — Thomas Wayne, Jr. src
Thomas suffered severe head injuries when he was struck by a car as a young child, and sustained permanent brain damage. Because he would always remain mentally unstable, and a danger to himself and society, his parents had no choice but to have him confined to a mental institution, Willowood Asylum, for life. Thomas adopted the asylum's name, Willowood, as his new surname, as his family name was kept secret. Although Thomas and Martha Wayne had planned to tell Bruce about his long-lost brother when he was old enough, they never got the opportunity as they were murdered by Joe Chill before they could do so.
Thomas eventually escaped and was coerced into becoming an assassin called the Boomerang Killer. Batman, in reality Thomas's brother Bruce, learned of his existence and stopped him, also learning the identity of the man behind the killings. Later, Deadman seized control of Thomas's body and used it to resume his career as an acrobat. Batman, upon locating his brother, demanded that Deadman release him but, upon being freed, Thomas ended up impulsively taking a bullet intended for his brother, saving Batman's life at the cost of his own.
- The Crisis on Infinite Earths: The Compendium established that the books that had Thomas Wayne, Jr. took place on Earth-Thirty-Two. The actual existence of a Thomas Wayne, Jr. on Earth-One is unknown.
- 2 Appearances of Thomas Wayne, Jr. (Earth-One)
- 1 Images featuring Thomas Wayne, Jr. (Earth-One)
- 1 Quotations by or about Thomas Wayne, Jr. (Earth-One)
- Character Gallery: Thomas Wayne, Jr. (Earth-One)