Nathan Fillion (born March 27, 1971) is a Canadian actor who is best known for his roles as Malcolm Reynolds on the Fox space western drama series Firefly in 2002 and its 2005 continuation film Serenity, Captain Hammer in Dr. Horrible's Sing-Along Blog, Richard Castle on the ABC crime drama series Castle from 2009 to 2016 and for voicing Hal Jordan in various DC Comics animated movies.
- Johnny J. Worthington, III in the 2013 Disney/Pixar movie Monsters University.
- Preston Northwest in Gravity Falls
- Blue Inmate in Guardians of the Galaxy
- Simon Williams in Guardians of the Galaxy Vol. 2
- Richard Castle in Castle