Characters from The Wednesday Wars have appeared in Schmidt's other novels.
The novel Okay for Now features Holling's friend and classmate Doug Swieteck as the main character. Holling appears in the first chapter of the novel to say goodbye to Doug, who is about to move. Several times, the novel refers back to a scene from The Wednesday Wars, in which Doug meets Joe Pepitone.[1]
Lucas Swieteck, Doug's older brother, appears as Jack and Joseph's gym coach in Orbiting Jupiter, set many years later.[2]
Just Like That, released in January 2021, features Meryl Lee Kowalski as its main character.
The Labors of Hercules Beal is also set many years later. Holling's friend Danny Hupfer is the titular Hercules' teacher.