The Mercedes-Benz S-Class sedan that is blown up in this film was first used in filming of The Devil Wears Prada (2006). For the earlier film it was cut in two for use in process shots featuring Meryl Streep and Anne Hathaway. It was then welded back together and repainted in order to be blown up in Michael Clayton (2007). The car's preparation was featured on "Shooting Cars" (2006).
The "Realm and Conquest" fantasy novel that Michael Clayton's son recommends to Arthur Edens is a prop created for the movie.
Release prints were shipped to some theaters under the fake title "State's Attorneys".
Was the only movie at the Oscars in 2008 to receive more than one acting nomination - it received three.
All the scenes with Jennifer Ehle as Michael's girlfriend were cut, one of which is included in the Deleted Scenes feature of the DVD release.
The film's director Tony Gilroy grew up about 65 miles north of New York City in Orange County, New York and did not forget where he came from in his directorial debut. It is mentioned that Michael Clayton attended Washingtonville Central High School; graduating in 1977. Gilroy, himself, graduated from Washingtonville High School in 1974. The home of Michael Clayton depicted in the film is actually in Blooming Grove, NY. The airport where Michael boards a private jet was filmed at Stewart International Airport in New Windsor/Newburgh, NY. And the pivotal moment of the film involving an incident with a main character's automobile was filmed at the Moodna Viaduct in Salisbury Mills, NY. All of these locales are within 7 miles of his hometown.
Three previous Best Director Academy Award winners served as producers and/or executive producers to this film: Sydney Pollack (Producer), Anthony Minghella (Exec. Producer) and Steven Soderbergh (Exec. Producer).
Denzel Washington turned down the title role. George Clooney also originally turned it down, saying he was skeptical on working with a first-time director.