The lead role was offered to Chris Hemsworth but he passed on the role due to scheduling issues. Then, it came up that the producers would invite the actor and singer Gustavo Goulart to perform the lead role (Mitch Rapp), but this rumor was never confirmed.

Young actor Dylan O'Brien won the part of 'Mitch Rapp' beating more established older actors. Being in his mid 20's, the hope is that the actor grows as the envisioned movie series progresses. Also, since 'American Assassin' is based on a prequel novel, it provides the opportunity to start at the very beginning of the Rapp characters' career.

'American Assassin' is one of fifteen novels by Vince Flynn set in the world of counter-terrorism operative Mitch Rapp. Every single one has been a New York Times best-seller, the three most recent entries have been number one New York Times best-sellers, and the series has sold nearly 20 million copies as of Oct 2015..

Bruce Willis was attached to play the mentor of Mitch Rapp

CBS Films also bought the movie rights to "Consent to Kill", the eighth book in chronological order of the Mitch Rapp universe.

American Assassin is the 11th book in Vince Flynn's series, but the first book in chronological order.

Established actors Gerard Butler, Colin Farrell and Matthew Fox were considered for playing the lead role 'Mitch Rapp'.

In the books, Mitch Rapp's girlfriend was killed in the Pan Am flight that was blown up by a terrorist over Lockerbie Scotland. The movie seems to show her dying on the beach.

A first look picture of Dylan O'Brien as 'Mitch Rapp' was released on September 12, 2016.

Film production needed to start by 2016 or the rights to the film would be reverted to the Vince Flynn Estate.

Principal photography began in London, Rome and Budapest in September 2016.

Director Antoine Fuqua was originally attached to direct.

Veteran stuntman and martial arts world champion Buster Reeves (Instructor) and Michael Keaton (Stan Hurley) share the Batman mantle. Reeves doubled for Christian Bale and performed Batman's stunt fighting in the Dark Knight trilogy while Keaton played the caped crusader in Batman (1989) and Batman Returns (1992).

Jeffrey Nachmanoff and Edward Zwick were also attached as director when movie was in production stage, back in 2012.

Includes three actors from several Marvel franchises. Sanaa Lathan played Vanessa in Blade (1998), Scott Adkins played Lucian in Doctor Strange (2016), and Taylor Kitsch who played Remy LeBeau (Gambit) in X-Men Origins: Wolverine.