After Superboy-Prime attacked Conner Kent (Superboy) in Smallville and injured or killed many Teen Titans, Bart joined with Flashes Wally West and Jay Garrick to stop the rampage of Superboy-Prime by running him at top speed into the Speed Force. Jay reached his limit before entering the Speed Force and Wally turned into energy and vanished, leaving Bart alone with Superboy-Prime. Barry Allen, Johnny Quick and Max Mercury, all of whom had previously been absorbed into the Speed Force, appeared and aided Bart. After taking Superboy-Prime into the Speed Force, Barry told Bart that "Wally is waiting for you". After they disappeared, Jay claimed that the Speed Force was gone.

Bart spent four years in an alternate reality's Keystone City, with Max, Barry, Wally, and an alternate version of Jay Garrick. There Superboy-Prime managed to escape from his prison, and the alternate Jay failed to stop him. All the speedsters rallied together to return to their dimension so they could warn everyone about Superboy-Prime. However, they knew that not even the fastest men alive could get there before the insane Boy of Steel. Barry suggested to Wally that he somehow absorb the entire Speed Force, but cautioned that it might kill him. Bart bravely volunteered, because Wally had his family to think of, and Barry was incapable of it because he was already dead. Wally handed him the ring and Barry gave Bart his Flash suit, which would both help Bart survive his journey.

Bart reappeared in Tokyo wearing his grandfather's costume. He later helped the heroes against the army of escaped supervillains in the Battle of Metropolis. Bart then explained to the nearby Wonder Girl that his grandfather's uniform was the only thing that could survive the trip back from where he had been, and that he was the only one there "who could still run". Bart then unleashed his anger against Superboy-Prime for killing Conner Kent, pummelling him at super-speed and forcing Superboy to retreat from the battle. When the crisis was over, Bart explained to Jay that he had spent years in an unknown dimension where he grew older. Bart confirmed that the Speed Force was destroyed and that he had used up the residual speed locked in his body fighting in Metropolis. He gave Barry's costume to Jay and said that Jay was once again the fastest man alive.

After about a year pretending to be powerless, Bart eventually was forced to reveal that the Speed Force has been inside him all along in order to defeat a rogue pseudo-speedster. After a very brief tenure as The Flash, he was attacked by Inertia and the Rogues, who drained him of the Speed Force and beat him to death. Ironically, Wally West was returned to New Earth by the Justice League at almost the same time, sadly a little too late to help his protege. Bart is survived by West, his grandmother Iris and girlfriend Valerie.