Who played the character Lewis Strauss in Oppenheimer?

Robert Downey Jr. played Lewis Strauss in Oppenheimer. In the film, Downey portrays Rear Admiral Lewis Strauss, a former Naval Reserve officer and senior member of the U.S. Atomic Energy Commission.

Strauss is one of the film’s major figures outside J. Robert Oppenheimer’s scientific work. The story presents his political and personal conflict with Oppenheimer through the 1954 security hearing, while also using Strauss’s later confirmation hearing as a framing device. These interwoven timelines gradually reveal his influence over Oppenheimer’s professional downfall.

The role marked a major dramatic turn for Downey, who had become especially associated with Tony Stark in Marvel films. His performance earned the Academy Award for Best Supporting Actor at the 96th Academy Awards. Benny Safdie, one of the listed alternatives, played physicist Edward Teller, not Strauss.