Nathan Fillion is a Canadian and American actor. He played the leading roles of Captain Malcolm "Mal" Reynolds on Firefly and its film continuation Serenity, and Richard Castle on Castle. As of 2018, he stars as John Nolan on The Rookie and was an executive producer on the show as well as its spin-off series, The Rookie: Feds.

Malcolm "Mal" Reynolds is a fictional character and the protagonist of the Firefly franchise. Mal is played by actor Nathan Fillion in the 2002 TV series Firefly and the 2005 film Serenity. In the series, Mal is a former Browncoat sergeant and the captain of the "Firefly-class" spaceship Serenity. The character was named at No. 18 in TV Guide's Greatest Sci-Fi Legends list in 2004.