Who's This? Who's Who vol.XI, p.26.
How you could have heard of him: Though he's made a forgettable appearance here and there since Who's Who - in Eclipso, for example, and Starman - he should be most easily remembered from a recent storyline in Justice League Dark, where he appeared with brown hair so we could tell him apart from John Constantine.
Example story: Sensation Comics #107 (1952)
Who else? We're off to volume XII next! There's a good chance we'll see a martial artist in that batch!