‘Oppenheimer’ – Who Does Matt Damon Play?


The Big Picture

  • Oppenheimer is a three-hour epic biopic with a colossal cast, including Cillian Murphy, Robert Downey Jr., and Matt Damon.
  • Lt. General Leslie Groves played a crucial role in the Manhattan Project, overseeing the construction, development, and deployment of the atomic bomb.
  • Matt Damon brings his acting prowess to the role of Groves, playing the hard-ass military man and providing a compelling foil to J. Robert Oppenheimer’s intellectual scientist.

Christopher Nolan‘s wildly successful summer blockbuster biopic Oppenheimer is a three-hour epic with a colossal cast. The film’s pivotal players include key folks responsible for the development of the atomic bomb. Alongside Cillian Murphy in the titular role, we have Robert Downey Jr. playing Lewis Strauss, Emily Blunt as Kitty Oppenheimer, Florence Pugh as Jean Tatlock, and Tom Conti as Albert Einstein, and that’s not even a fraction of the whole cast!

One of the other main players in the film is Matt Damon, who plays another critical figure in the Manhattan Project named Leslie “Dick” Groves. Groves was a lieutenant general in the United States Army and worked side by side with J. Robert Oppenheimer on the progress of the deadly weapon and pushing things through on the military side of the operation. His involvement was crucial in the making of “Fat Man” and “Little Boy” and their usage against the Japanese at Hiroshima and Nagasaki in 1945 effectively ended World War II.


The story of American scientist, J. Robert Oppenheimer, and his role in the development of the atomic bomb.

Release Date
July 21, 2023



Main Genre

War , Biography , Drama

Who Was Lt. General Leslie Groves?

According to the National Museum of Science and History, Leslie Groves was born in 1896 in Albany, New York. After graduating from West Point, he entered the Army Corps of Engineers in 1918 where he would begin a series of supervisory positions involving the oversight of hundreds of thousands of men and several billion dollars in funds on the construction of things like base camps, munitions plants, depots, air bases, hospitals, airplane plants, and the massive undertaking that was the United States Pentagon, which he completed building in under 18 months in 1942. So when his superiors were looking for someone to oversee the day-to-day activities of the Manhattan Project, Groves was an easy choice with his illustrious track record of getting things built in a timely and efficient manner.

What Was Leslie Groves’ Role in the Manhattan Project?

Though the bomb wouldn’t be dropped until August 1945, the government was already taking action to build it three years prior during the early stages of the Cold War. In September 1942, Groves was appointed to head the Manhattan Project with the rank of Temporary Brigadier General. His involvement in the project was all-encompassing and included the scientific and technical aspects of the bombs as well as the process development, construction; production; security, and military intelligence of enemy activities (particularly the Soviet Union and Japan).


‘Oppenheimer’s Most Explosive Scene Isn’t the One You Think

Oppenheimer turns a short speech into an explosive moment of inner turmoil.

Atomic research was also conducted under Groves’s watch at the University of Chicago and Columbia University in New York. Perhaps most importantly, Groves was also in charge of determining how and when the bomb would be deployed upon its completion. It was an enormous assignment and Groves proved with his no-nonsense and oftentimes gruff approach that he was the right man for the job.

What Kind of Man Was ‘Oppenheimer’s Lt. General Leslie Groves?

There is a quote provided by the National Museum for Nuclear Science and History that says just about everything you need to know about Leslie “Dick” Groves. It was a district engineer at the Manhattan Engineer District named Kenneth D. Nichols, who was a Colonel under Groves who summed up the man saying, “First, General Groves is the biggest S.O.B. I have ever worked for. He is most demanding. He is most critical. He is always a driver, never a praiser. He is abrasive and sarcastic. He disregards all normal organizational channels. He is extremely intelligent. He has the guts to make timely, difficult decisions. He is the most egotistical man I know. He knows he is right and so sticks by his decision. He abounds with energy and expects everyone to work as hard, or even harder than he does… if I had to do my part of the atomic bomb project over again and had the privilege of picking my boss, I would pick General Groves.”

Groves and Oppenheimer were two very different men. While Groves was a hard-driven, squared-away bordering on narcissistic military man, J. Robert Oppenheimer was a more dynamic individual and a pensive thinker who often struggled with the weight of the sheer enormity of what they were doing with the Manhattan Project in Los Alamos, New Mexico. As odd a couple as they were, Groves personally selected Oppenheimer even amid swirling rumors at the time that the brilliant scientist had ties to the Communist Party. He also waived the normal security clearance process for Oppenheimer in order to get him started on the bomb’s development in a more expeditious fashion as he knew that time was of the essence with the Soviet Union and Japan having also started research on a similar weapon.

What Does Matt Damon Bring to His Role in ‘Oppenheimer’?

Matt Damon looking up at something in The Informant!
Image via Warner Bros.

Oppenheimer isn’t Matt Damon’s first on-screen rodeo by a longshot. The award-winning actor has proven that he has the mettle to play a hard ass like Groves before in the Bourne franchise and has excelled in other real-life roles including as Carroll Shelby in Ford v. Ferrari and as James Granger in another military-themed film The Monuments Men in 2014. Damon holds his own against one of the best ensemble casts of recent memory in Nolan’s biopic. As Groves, Matt Damon plays the odd couple army man foil against Oppenheimer’s intellectual scientist. When Groves later, long after the war, gives testimony in Oppenheimer’s case, he navigates that tricky morality line with grace, both maintaining honesty and defending Oppenheimer how he can when the tides have turned against him – embodying a commitment to his morals that feels honorable.

Oppenheimer is available to rent on Apple TV+ in the U.S.

Watch on Apple TV+


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