This is the first movie in the Iron Man franchise not to be directed by Jon Favreau, possibly over creative differences with Marvel or because of his salary demands. He later said that not directing allowed him to have more fun with his character "Happy" Hogan, saying that he was like "a proud grandfather, who doesn't have to change the nappies, but gets to play with the baby."
The idea that "Happy" Hogan's favorite television show is Downton Abbey (2010) was at the suggestion of Jon Favreau, who is actually a big fan of the British series.
Robert Downey Jr. pushed to get Gwyneth Paltrow to have some action scenes, and producer Kevin Feige approved: "We are bored by the damsel in distress. But sometimes we need our hero to be desperate enough in fighting for something, other than just his own life. So, there is fun to be had with 'Is Pepper in danger, or is she the savior?' over the course of this movie."
The first Iron Man movie to gross over $1 billion, and the second Marvel movie to reach this mark, with The Avengers (2012) being the first.
The first cut was three hours and 15 minutes long. The final cut was two hours and 10 minutes long.
Joan Rivers: As herself. This was her last appearance in a theatrical film before her death in 2014.
Shane Black: [Christmas] Except for the prologue, the whole movie is set at Christmastime. Black's Lethal Weapon (1987), The Last Boy Scout (1991), The Long Kiss Goodnight (1996), and Kiss Kiss Bang Bang (2005) were also set at Christmastime. Last Action Hero (1993), which Black did not direct but helped write had at least a partial Christmas setting.
Shane Black: Robert Downey Jr. sitting on the floor and leaning on a car (like in Kiss Kiss Bang Bang (2005))