Originally born on Earth-Two as the son of the criminal Brainwave and Gimmick Girl (who was originally written as being tricked into the relation but later openly acceptant of her husband) Hank Jr. was revealed to have inherted his father's superhuman mental abilities.
Hank Jr. would remain mostly hidden from the condemnation of his famous parents until he attained early adulthood and sought to actively pursue an active crime-fighting career in some measure to atone for his father's past deeds in his uncle, Sylvester Pemberton, Jr., the original Star-Spangled Kid who was forming a new superhero group called Infinity, Inc.. Following his father's death, he dropped the 'Jr.' from his name and began calling himself just 'Brainwave'.
Infinity, Inc. consisted of many of the direct children and successors of the Justice Society members. Despite their youth the team proved their effectiveness when they defeated their elder heroes when the Justice Society was possessed by the Stream of Ruthlessness. While a member of Infinity, Inc., Hank met and became romantically attached to Jade the daughter of Alan Scott. Despite his best attempts the relationship ended badly.
- Although this character was originally introduced during DC's Earth-Two era of publication, their existence following the events of the 1985–86 limited series Crisis on Infinite Earths remains intact. However, some elements of the character's Pre-Crisis history may have been altered or removed for Post-Crisis New Earth continuity, and no longer apply.
- Brainwave once dated Jade.
- Brainwave is somewhat mentally unstable. Early in the development of his powers he had a tendency to create illusions subconsciously that could fool even himself. According to Doctor Mid-Nite, Brainwave has an abnormal mass of nerve fibers leading from his auditory cortex to a growth on the side of his inferior colliculus in his brain which he hypothesized is what drives him insane and gives him his telepathic abilities.
- 97 Appearances of Henry King, Jr. (New Earth)
- 17 Images featuring Henry King, Jr. (New Earth)
- Quotations by or about Henry King, Jr. (New Earth)
- Character Gallery: Henry King, Jr. (New Earth)
Justice Society of America member
Legion of Doom member