Who's This? A TALL brain more than a BIG brain.
How you could have heard of him: It's more likely you heard of the guys who co-opted his nom de guerre. Well, maybe not the one who was in S.T.A.R. Corps, but Dominic Lense, the Mister Terrific villain who turned up in the Flash TV show. Not the same person or shtick.
Example story: Justice League of America #36 (June 1965) "The Case of the Disabled Justice League!" by Gardner Fox, Mike Sekowsky and Bernard Sachs
Brain Storm was never gonna make it out of the Silver Age as a major player for three reasons:
1) He looks silly.
2) His powers are too great and ill-defined.
3) He's actually pretty dumb.
At the core is a Batman villain who gets psychotic "inspirations" from the stars, but to play against the JLA, he needs an advantage, and that advantage is also his downfall (see points 1 and 2). Oh well.
Who's Next? A myopic JSA villain.