Philippe Petit personally trained Joseph Gordon-Levitt how to walk on a tightrope. When the training started, Petit predicted that Gordon-Levitt would need no more than eight days of training to be able to walk on a wire alone, which came true.
During the New York City premiere, the realism of the climax caused some viewers to actually throw up from vertigo, at least one reviewer claimed that. Director Robert Zemeckis responded, he didn't believe that report, but "(the goal) was to evoke the feeling of vertigo. We worked really hard to put the audience up on those towers and on the wire."
While attending Columbia University from 2000 to 2004, Joseph Gordon-Levitt studied French poetry and became an avid Francophile. He already spoke French before he began working on this movie.
The names of six of the N.Y.P.D. rooftop police officers, Genco, Tessio, Hagan, Sollozzo, Cicci, and Clemenza, directly refer to The Godfather (1972).
To help get an idea of the distance and height of the climactic wire walk, Joseph Gordon-Levitt went to the World Trade Center memorial, where there are two pools representing where the towers originally stood, and walked the distance between them. He also recounted his own experience when he visited the observation deck on top of one of the towers in the summer of 2001, saying of the sensation of being at such a height, "It felt more like being in the sky than being on a tall building."
Tom Hanks: as the voice of the security guard on the roof who is summoned downstairs for pizza. Hanks previously starred in two Robert Zemeckis movies, Forrest Gump (1994) and Cast Away (2000).