In the first episode "Secret Origins" of the "Justice League" animated series which aired in 2001, Flash was one of the heroes (along with Green Lantern, Hawkgirl, and Wonder Woman) summoned to aid Superman, Batman, and J'onn J'onzz in defeating the Imperium invasion.
In the aftermath of that conflict, Superman suggested that the seven heroes band together to form the Justice League. Flash, appropriately enough, was the first to agree to Superman's proposal.
In DC Comics continuity, Wallace "Wally" West is the third person to take up the mantle of the "Flash". Jay Garrick was the first, Barry Allen the second, and Bart Allen was (albeit briefly) the fourth.
In DC comics, Wally West's most notable occupation was that of a police mechanic; Barry Allen was a police chemist. Since Wally West's DC Animated Universe occupation is that of a police scientist, it is possible that the characters have simply been merged, with Barry Allen never existing in the DC Animated Universe at all.
The description for Flash, real name Wally West, is commonly known as the "Fastest Man Alive" and is a popular superhero from Central City as well as founding member of the Justice League.
Flash used little in the way of specialized equipment. His costume could be compressed to a tiny fraction of its ordinary size, allowing it to be stored in a hidden compartment within a specially-designed ring. He could therefore carry his costume with him at all times, allowing him to respond instantly to any unexpected situation that might require his attention.
Flash equivalent from Marvel? Quicksilver, brother of Scarlet Witch and mutant.