Joshua Dysart (Unknown Soldier) and Khari Evans (Carbon Grey) will tackle the tale of super-powered teenagers.
"The idea of really getting a chance to dig in and build an epic mythology populated by a fully-realised cast of characters, all centred around Jim Shooter and David Lapham's original premise, is super-exhilarating to me," said writer Dysart.
"I've been looking for a book to write that could be dark, weird, trippy, fun, real, unreal, violent and thematically ambitious. All the things I look for in fantastic fiction myself. Harbinger is that book, so I'm pretty damn excited about it."
The original storyline focused on antagonist and powerful psionic Toya Harada.
His former student Peter "Sting" Stanchek formed a team of heroes to combat Harada and his sinister Harbinger Foundation.
Valiant has also announced an X-O Manowar revival as part of its relaunch.
Sony Pictures recently acquired the film rights to the publisher's Bloodshot property.
Harbinger will relaunch on June 6.