He was brilliant and did what had never been done before. Unfortunately

How can anybody be proud of the atomic bomb???

Oppenheimer’s famous quote (something like “I have become death, destroyer of worlds,” which he apparently said after witnessing the explosion of the first atomic bomb) seems to support the common belief that he was the “inventor” of the atomic bomb. But no single person can claim that distinction, and, even if you had to point to one person as contributing the most to the bomb’s creation, I think it would be Enrico Fermi or maybe Leo Szilard. They both formulated more of the science underlying the bomb than Oppenheimer, who was a great physicist but made his primary contributions as an administrator. Oppenheimer was the manager of the unthinkably complex Manhattan Project, which certainly required a thorough knowledge of science, but also required the ability to get a lot of strong personalities to work together, to manage an enormous budget, to serve as an interface between the scientists and the government (maybe the toughest job of all), and to act as almost the mayor of the town Los Alamos that grew up around the Manhattan Project. In almost all of those areas, Oppenheimer did a remarkable job, given the circumstances, and his leadership, by most accounts, ensured that the Allies were given the option of using the atomic bomb as an offensive weapon soon enough to make a difference in the war with Japan. Whether or not you agree that the bomb should have been developed at all, it’s difficult to argue that Oppenheimer did anything less than an exceptional job developing it.