Nathan Fillion

Best known since Firefly for Castle and The Rookie, plus Guy Gardner in DC Studios' Superman and HBO's Lanterns.

After the show

Nathan Fillion played Caleb, the misogynist preacher who served the First Evil, in the final five episodes of Buffy the Vampire Slayer in 2003, and returned as Captain Malcolm Reynolds in the 2005 film Serenity.

He followed with the horror comedy Slither (2006) and Waitress (2007), the Fox series Drive (2007), and a run as Dr. Adam Mayfair on Desperate Housewives (2007 to 2008). In 2007 he co-founded the literacy nonprofit Kids Need to Read with author PJ Haarsma. In 2008 he played Captain Hammer in Joss Whedon’s web musical Dr. Horrible’s Sing-Along Blog.

From 2009 to 2016 he starred as novelist Richard Castle in ABC’s Castle. Along the way he voiced Hal Jordan in several DC animated films starting in 2011, played Dogberry in Whedon’s Much Ado About Nothing (2012), voiced Cayde-6 in the Destiny games from 2014, and co-created the web series Con Man (2015 to 2017) with Alan Tudyk.

Since 2018 he has starred as John Nolan, and served as an executive producer, on ABC’s The Rookie. He also appeared in James Gunn’s The Suicide Squad (2021) and Guardians of the Galaxy Vol. 3 (2023), and played Green Lantern Guy Gardner in DC Studios’ Superman (July 2025). In May 2025 Concordia University of Edmonton gave him an honorary doctor of laws.

In a June 2022 appearance on Michael Rosenbaum’s Inside of You podcast, Fillion said he knew of the complaints about Whedon’s conduct, but that the reporting did not mention Firefly and “that was not my experience with that man.” He said, “I would work with him again in a second,” and added, “by his own admission that guy’s a work in progress and I appreciate that.”

Lately

The Rookie aired its eighth season from January to May 2026, and ABC renewed it for a ninth in April 2026. In May 2026 ABC ordered the spinoff The Rookie: North, starring Jay Ellis, with Fillion as an executive producer. He guest starred in the series finale of the Canadian drama Family Law (spring 2026).

He returned as Guy Gardner in HBO’s Lanterns, which premiered August 16, 2026, and is listed for the film Man of Tomorrow (2027). In July 2026 Dark Horse launched Witness Point, a four-issue crime comic he co-wrote with Heath Corson, with art by Soo Lee.

In November 2025 he and Alan Tudyk launched the podcast Once We Were Spacemen. At a live taping at Awesome Con in Washington, D.C., in March 2026, Fillion announced that an animated Firefly series is in development through his company Collision33 and 20th Television Animation, with the original cast expected to return. Marc Guggenheim and Tara Butters are attached as showrunners. Fillion said Whedon is not involved but has given the project his blessing. As of October 2026 no network or streaming home has been announced.

Off screen

Fillion is a longtime supporter of Kids Need to Read, and his fundraising with Charity: Water raised more than $60,000 in 2019.