Lee Child, the source novelist, plays a TSA agent who is seemingly ambivalent to the fact that Jack (Tom Cruise) does not really match the stolen ID he is using to board the plane. This is a nod to Child's support of the "controversial" casting of the diminutive 5' 7" tall Cruise as Child's 6' 5" tall, 250 lb with a 50-inch chest Jack Reacher. Despite a lot of fan backlash at the casting of Cruise, Lee responded, "Obviously, Cruise doesn't match the physical description of Reacher in the books, but the movie is not going to match the book anyway."
Cobie Smulders spent eight weeks training in various martial arts to prepare for her role in this film.
The shirt Jack Reacher wears in the first diner scene is the same shirt he wears throughout Jack Reacher (2012).
While speaking to Jack Reacher on the phone, Susan Turner mentions that she's sitting in his old office. She asks him about a huge dent on top of the desk that allegedly was caused by Jack slamming someone's head onto it. This comes from a conversation the two had over the phone in the novel "61 Hours". During the conversation, Susan asks Jack if the rumor is true that the head he slams belonged to a Colonel Jack didn't like; he denies it.