- "The Manhattan Project took a lot out of both of us."
- —Talking to Emmett Brown
Leslie Groves, of the U.S. Army Corps of Engineers, led the Manhattan Project. He had the rank of Major General during his time on the Manhattan Project. After the war, he was promoted to the rank of Lieutenant General.
In 1962, he came to Emmett Brown with the hope that he could invent machine that would allow time travel, so they could prevent the Cuban Missile Crisis from ever happening. After having regrets about accepting their offer, Doc used his prototype temporal field capacitor to send a message to himself in the past. This caused an electrical fire, which burned down the Brown family mansion, preventing Groves from ever asking Emmett about time travel.