Marvel Cinematic Universe star Robert Downey Jr. is officially an Academy Award winner! The actor knownbest for playing Iron Man/Tony Stark just took home the prize for Best Supporting Actor for his portrayal of Lewis Strauss in Christopher Nolan's Oppenheimer. Downey Jr. has been the frontrunner this season, taking home a BAFTA, SAG Award, Golden Globe, and more. The actor won the Oscar tonight over Robert De Niro (Killers of the Flower Moon), Ryan Gosling (Barbie), Mark Ruffalo (Poor Things), and Sterling K. Brown (American Fiction).