- Nathan Fillion is one of the actors who have portrayed multiple characters in the Marvel Cinematic Universe.
- Nathan Fillion is one of the actors to portray characters for both Marvel Studios and Pixar, both of which are owned by Walt Disney Pictures. He voiced Johnny J. Worthington III in Monsters University and Mr. Sterling in Cars 3.
- Nathan Fillion previously worked with James Gunn in Slither and Super, and with Joss Whedon in Firefly, Buffy the Vampire Slayer, Dr. Horrible's Sing-Along Blog and Much Ado About Nothing.
- Nathan Fillion previously dated his Guardians of the Galaxy co-star Mikaela Hoover.
- Nathan Fillion was in talks to play Hank Pym in The Avengers before it was decided that Pym would not appear in the film.
- Nathan Fillion voiced Hal Jordan/Green Lantern in the DC Universe Animated Original Movies Green Lantern: Emerald Knights, Justice League: Doom, Justice League: The Flashpoint Paradox and Justice League: Throne of Atlantis.
- Nathan Fillion previously worked with Vin Diesel in Saving Private Ryan.
- Nathan Fillion previously worked with Michael Rooker in Slither and Super.
- Nathan Fillion previously worked with Sean Gunn in Super.