J. Robert Oppenheimer

The Director of the Manhattan Project

Nuclear physicist Julius Robert Oppenheimer testifying before the Special Senate Committee on Atomic Energy. Getty Images

Who Was J. Robert Oppenheimer?

J. Robert Oppenheimer, a physicist, was the director of the Manhattan Project, the U.S.'s attempt during World War II to create an atomic bomb. Oppenheimer's struggle after the war with the morality of building such a massively destructive weapon epitomized the moral dilemma that faced scientists who worked to create the atomic and hydrogen bombs.

Dates: April 22, 1904 -- February 18, 1967

Also Known As: Julius Robert Oppenheimer, Father of the Atomic Bomb

Early Life of J. Robert Oppenheimer

Julius Robert Oppenheimer was born in New York City on April 22, 1904, to Ella Friedman (an artist) and Julius S. Oppenheimer (a textile merchant). The Oppenheimers were German-Jewish immigrants but did not keep the religious traditions.

Oppenheimer went to school at the Ethical Culture School in New York. Although J. Robert Oppenheimer easily grasped both the sciences and humanities (and was especially good at languages), he decided to graduate from Harvard in 1925 with a degree in chemistry.

Oppenheimer continued his studies and graduated from the University of Gottingen in Germany with a PhD. After earning his doctorate, Oppenheimer traveled back to the U.S. and taught physics at the University of California at Berkeley. He became well known for being both a fantastic teacher and a research physicist - not a common combination.

The Manhattan Project

During the beginning of World War II, news arrived in the U.S. that the Nazis were progressing towards the creation of an atomic bomb. Though they were already behind, the U.S. believed they could not allow the Nazis to build such a powerful weapon first.

In June 1942, Oppenheimer was appointed the director of the Manhattan Project, the U.S.'s team of scientists who would work to create an atomic bomb.

Oppenheimer threw himself into the project and proved himself not only a brilliant scientist, but also an exceptional administrator. He brought the best scientists in the country together at the research facility at Los Alamos, New Mexico.

After three years of research, problem solving, and original ideas, the first small atomic device was exploded on July 16, 1945 in the lab at Los Alamos. Having proved their concept worked, a larger scale bomb was built. Less than a month later, atomic bombs were dropped on Hiroshima and Nagasaki in Japan.

A Problem With His Conscience

The massive destruction the bombs inflicted troubled Oppenheimer. He had been so caught up in the challenge of creating something new and the competition between the U.S. and Germany that he - and many of the other scientists working on the project - had not considered the human toll that would be caused by these bombs.

After the end of World War II, Oppenheimer began to voice his opposition to creating more atomic bombs and specifically opposed developing a more powerful bomb using hydrogen (the hydrogen bomb).

Unfortunately, his opposition to the development of these bombs caused the United States Atomic Energy Commission to examine his loyalty and questioned his ties to the Communist Party in the 1930s.

The Commission decided to revoke Oppenheimer's security clearance in 1954.


From 1947 to 1966, Oppenheimer worked as the director of the Institute for Advanced Study at Princeton. In 1963, the Atomic Energy Commission recognized Oppenheimer's role in the development of atomic research and awarded him the prestigious Enrico Fermi Award.

Oppenheimer spent his remaining years researching physics and examining the moral dilemmas related to scientists. Oppenheimer died in 1967 at age 62 from throat cancer.