Robert Downey Jr. plays Iron Man, whose civilian identity is Tony Stark when he is not fighting crime. Stark is a wealthy industrialist, inventor, and major figure in Marvel's superhero universe.
In the 2008 film Iron Man, Stark inherits and runs Stark Industries, a company that manufactures advanced weapons. After being captured by terrorists and seriously injured, he builds an armored suit to escape. He later improves the design and uses the technology to become the armored hero known publicly as Iron Man.
Tony Stark's identity is central to the character: he has no supernatural powers, relying instead on engineering, artificial intelligence, energy systems, and successive suit upgrades. His intelligence, confidence, humor, and personal flaws distinguish him from a generic masked hero.
The most common confusion is reversing the identities. Iron Man is Stark's superhero alias, while Tony Stark is the man inside the armor. Downey's portrayal began with Iron Man in 2008 and continued through the Marvel Cinematic Universe, making the pairing one of modern superhero cinema's best-known character identities.