He was interviewed for the documentary Marvel Studios: Assembling a Universe.
- He won a Saturn Award for Best Director for his work on Guardians of the Galaxy.
- Together with Nicole Perlman, he was nominated for a Saturn Award for Best Writing for his work on Guardians of the Galaxy.
- Together with Nicole Perlman, he was nominated for a Writers Guild of America Award for Best Adapted Screenplay for his work on Guardians of the Galaxy.
- James Gunn cast many of his former collaborators in the films Slither and Super into Guardians of the Galaxy, such as Michael Rooker, Gregg Henry, Nathan Fillion, Rob Zombie, Stephen Blackehart and Mikaela Hoover.
- James Gunn cast his own brother and frequent collaborator Sean Gunn for multiple roles in Guardians of the Galaxy.
- James Gunn cast his own dog Wesley Von Spears to portray a Holographic Dog in Guardians of the Galaxy.
- James Gunn asked his mentor Lloyd Kaufman to make a cameo in the film, like he did in Gunn's previous films Slither and Super.
- James Gunn previously worked with Seth Green in Scooby-Doo 2: Monsters Unleashed.
- James Gunn is the third Marvel Cinematic Universe director to play a part in the film he is directing. The first was Jon Favreau, who portrayed Happy Hogan in Iron Man, Iron Man 2 and also in Iron Man 3 and Spider-Man: Homecoming, despite not directing the latter two. The second was Joe Russo, who portrayed Doctor Fine in Captain America: The Winter Soldier and Theo Broussard in Captain America: Civil War. The fourth was Taika Waititi, who portrayed Korg in Thor: Ragnarok.
- James Gunn filmed Stan Lee's cameos in Doctor Strange, Spider-Man: Homecoming and Thor: Ragnarok as well as Guardians of the Galaxy Vol. 2 to cut down travel time for the 93-year old comic book writer.
- James Gunn casted his own parents Jim Gunn Sr. and Leota Gunn in smaller roles in Guardians of the Galaxy Vol. 2.
- James Gunn wrote a treatment for a Silver Surfer movie in 1999.
- James Gunn was the only person at the 41st Saturn Awards to be nominated in two separate categories, Best Director and Best Writing.
- James Gunn is the first director of the Marvel Cinematic Universe to direct an entire trilogy of movies.