Final answer:
J. Robert Oppenheimer directed the project at Los Alamos that developed the first atomic bomb.
Step-by-step explanation:
The physicist who directed the project at Los Alamos that developed the first atomic bomb was J. Robert Oppenheimer. Oppenheimer was chosen to head the top-secret Manhattan Project, which aimed to build a deliverable atomic bomb. Under Oppenheimer's leadership, the project successfully detonated the first atomic explosion in July 1945 and dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki the following month.