After rising to fame on the classic (but short-lived) sci-fi series Firefly, Nathan Fillion spent much of the mid-to-late 2000s appearing in films like Slither and television shows like Desperate Housewives. He found his next big role in 2009 thanks to Andrew Marlowe, the screenwriter behind the films Air Force One and Hollow Man. Marlowe created Castle, a crime drama for ABC that crossed the police procedural with the murder mystery genre.
Fillion was cast in the lead role of Richard Castle, a best-selling mystery author who begins consulting on murder cases with homicide detective Kate Beckett (Stana Katic). The pairing of Fillion and Katic was not only TV magic, it was pure serendipity. Katic was one of more than 175 actresses who read for the part, but she was cast after producers saw her rapport with Fillion outside the audition room.
Castle scored solid ratings from the start, and ran for eight seasons and 173 episodes, ending in May 2016. It earned four Emmy nominations and won five People's Choice Awards during its run, a testament to its popularity among TV viewers.
Following is a breakdown of the main characters from Castle, and the actors who played them. Some spoilers for the series follow.
Richard Castle (Nathan Fillion)
When we first meet best-selling mystery writer Richard Castle, he has just finished his series of highly popular Derrick Storm mystery novels. He struggled to find inspiration for his next book until he was asked to consult with NYPD homicide detective Kate Beckett, who is investigating a series of murders similar to the murders in his books. After Castle helps Beckett solve the case, the Mayor insists the two continue to work together on future cases.
Beckett inspires him to write a new book with a new character based on her, named Nikki Heat. Beckett's no-nonsense attitude keeps Castle's ego in check, and she eventually helps him become a better, more empathetic person. Although it took several seasons, the two eventually start a relationship.
Related: Best Nathan Fillion Performances, Ranked
Nathan Fillion first turned heads in 1998, with a small but memorable role as "Minnesota" Ryan in Steven Spielberg's Saving Private Ryan. He then appeared in three seasons of Two Guys, a Girl, and a Pizza Place. In 2002, he was cast as the lead in Joss Whedon's sci-fi series Firefly, which only lasted one season, but became an instant classic.
He followed that with Serenity, the movie version of the series, as well as roles in Much Ado About Nothing, Percy Jackson: Sea of Monsters, Guardians of the Galaxy, and voiceover roles, including a character in Disney's Monsters University. After Castle ended, he went on to star in The Suicide Squad, Resident Alien, and Guardians of the Galaxy Vol. 3. In 2018, he began starring in The Rookie for ABC.
Kate Beckett (Stana Katic)
Kate Beckett dreamed of a career in law, but after her mother was murdered while she was in college, she joined the New York Police Department, eventually becoming a homicide detective. Her personal loss drives her to seek justice in every case she takes on. When Richard Castle is given permission to consult on her investigations, she voices her opposition, but won't admit that she's really a fan. Although she insists on keeping their relationship professional, eventually, the two become close.
Canadian-born Stana Katic had small roles in a number of hit shows early in her career, including Alias, 24, ER, and Heroes. She had a small but pivotal role in the James Bond film Quantum of Solace (2008) and turned heads later that year in the comic book film The Spirit. She was cast as Kate Beckett the following year. Since then, she starred in The Possession of Hannah Grace and Absentia. She also provided voices for Batman: Arkham City, Justice Society: World War II, and the voice of Lois Lane in Superman: Unbound.
Alexis Castle (Molly C. Quinn)
Alexis is Castle's only child. She's a smart, strong-willed young woman who is often more mature than her father. While Castle insists he never has to worry about her making a bad decision, he still worries about her, especially in matters of the heart.
Molly C. Quinn had her first major on-screen role in 2007's Walk Hard: The Dewey Cox Story. The Texarkana, Texas native has also had a number of voiceover roles, including Supergirl in Superman: Unbound. She also appeared in Doctor Sleep and Guardians of the Galaxy Vol. 3.
Martha Rodgers (Susan Sullivan)
Martha Rodgers is Richard's mother. She was a stage actress in her youth, and although she continues to act, she finds her roles more and more limited. She lives with Castle in his loft apartment, which gives her plenty of opportunities to interfere with his personal life. She's also on hand to give Richard some life advice when he needs it.
Susan Sullivan was a stage actress who rose to fame when she moved to television, appearing as Lenore on Another World in the 1970s and Maggie on Falcon Crest for over 200 episodes in the 1980s. Her extensive career in film and television includes roles in My Best Friend's Wedding, Dharma and Greg, and The Incredible Hulk.
Javier Esposito (Jon Huertas)
"Javy" is a homicide detective in the New York City Police Department's 12th Precinct. He and his partner Kevin Ryan are like brothers, and both are good friends with Beckett and Castle, often working cases together. He is a former member of the Army's Special Forces, and served in Iraq, joining the NYPD after the war. He and Medical Examiner Lanie Parish used to date but broke up, although feelings between the two remained.
Jon Huertas had his first credited role in a 1995 episode of Beverly Hills, 90210. His other TV credits include Sabrina the Teenage Witch and The Shield. He most recently appeared as Miguel on NBC's hit series This Is Us and reunited with Nathan Fillion for an episode of The Rookie.
Kevin Ryan (Seamus Dever)
Kevin Ryan is a detective in the 12th Precinct of the New York City Police Department. He and his partner Javier Esposito are very close, and he is good friends with Beckett and Castle. Although he seems more naive and less experienced than the other detectives, he has a secret that even Javier doesn't know about. As a young cop, he once went deep undercover with the Irish mafia, an assignment that comes back to haunt him.
Seamus Dever appeared in 45 episodes of General Hospital in 2008 as Dr. Ian Devlin. His other TV credits include Waco: The Aftermath, the DC live-action series Titans, Hunters, the Marvel series Legion, and CSI: Crime Scene Investigation. The Flint, Michigan native also appeared in the film Hollywoodland, and voiced a character for the video game hit Far Cry 5.
Lanie Parish (Tamala Jones)
Lanie Parish is a medical examiner for New York City and Kate Beckett's best friend. She's a fan of Castle's books and immediately sees the spark between Richard and Kate. She encourages Beckett to take a chance on having a relationship with Rick, but Kate is resistant. Lanie has an on-again, off-again relationship with Detective Javier Esposito, and gets jealous when she sees him with someone else.
Tamala Jones has appeared in Blue Streak, The Ladies Man, The Fresh Prince of Bel-Air, ER, The Tracy Morgan Show, and 9-1-1: Lone Star. Just before the eighth season of Castle ended, it was announced that both Jones and Stana Katic were not asked to return for a potential ninth season due to "budget cuts." However, the series was later canceled by ABC, and not renewed.
Captain Roy Montgomery (Ruben Santiago-Hudson)
Captain Montgomery was the supervising officer at the 12th Precinct, and the boss of Beckett, Esposito, and Ryan. He was hugely supportive of his officers, and also supportive of Richard Castle working with Beckett on cases because the mayor asked him personally. His character is killed at the end of Season 3 while trying to protect Beckett from the men who killed her mother. It is revealed that, as a young cop, Montgomery was part of a corruption ring that murdered Beckett's mother. He has spent his years as Beckett's captain protecting her, remorseful that he didn't save her mother from being killed.
Ruben Santiago-Hudson is a Tony Award-winning actor with an extensive career on the stage. His film credits include The Devil's Advocate, Shaft, American Gangster, and Selma. His TV credits include Law & Order, East New York, The Quad, Public Morals, and Lackawanna Blues, a TV movie that earned him an Emmy nomination as a producer for Outstanding Television Movie.
Captain Victoria Gates (Penny Johnson Jerald)
Captain Gates took over leadership of the 12th Precinct beginning in the fourth season of Castle, after the death of Captain Montgomery. As a former investigator with Internal Affairs, her by-the-book approach means she has little patience for Castle and his antics, although he tries constantly to get on her good side.
Penny Johnson Jerald has also starred in The Larry Sanders Show, Star Trek: Deep Space Nine, and 24, where she played First Lady Sherry Palmer. Jerald did not appear in the eighth and final season of Castle after new showrunners made major changes to the show.
Hayley Shipton (Toks Olagundoye)
Hayley joined the show in Season 8, as an investigator with Castle's new P.I. agency. The British native served in MI6 and was also a police officer and an insurance investigator. She becomes an important asset in Castle's new endeavor, and she and Alexis become good friends.
Nigerian native Toks Olagundoye moved from Britain to the United States to attend Smith College in Massachusetts and pursue a career in acting. She went on to have roles in Law & Order and The Neighbors, and recently appeared on the Paramount+ series Fatal Attraction. She is also a voice actress, with roles on Beavis and Butthead, DuckTales, American Dad!, and Tales of the Jedi.
Sidney Perlmutter (Arye Gross)
Sidney Perlmutter is a New York City medical examiner. Extremely intelligent and committed to his work, he and Castle share a combative professional relationship; he doesn't care for Rick's usual sarcasm, and is quick to return it with some of his own.
Arye Gross appeared in the films Minority Report and Gone in 60 Seconds. He has also had television roles in Better Call Saul, Designated Survivor, and The X-Files. He provided the voice for Lando Calrissian in the Return of the Jedi radio drama for NPR in 1996.
Vikram Singh (Sunkrish Bala)
Vikram became a major character in Season 8. He was a tech expert who helped Castle and Beckett hunt down Loksat, a CIA analyst connected to illegal activity with Sen. William Bracken and the murder of Kate's mother.
Sunkrish Bala had his first major acting role in a 2005 episode of CSI: NY. His other TV credits include The Mandalorian, Good Trouble, and the fourth season of The Walking Dead, where he played Caleb, the doctor in the prison where the survivors take refuge.
Jim Beckett (Scott Paulin)
Jim Beckett is Kate Beckett's father. The two have a complicated relationship, dating back to the murder of Kate's mother when she was in college. He became an alcoholic afterward, although Kate helped him get sober. He has deep concerns about Kate's job and her continued investigation into her mother's murder.
Related: Castle: Where the Cast is Today
Scott Paulin has had major roles in film and television dating back to the 1980s, including The Right Stuff, Teen Wolf, Turner & Hooch, and Beverly Hills, 90210. Castle was his last on-screen acting role.
Jenny Ryan (Juliana Dever)
Jenny was Kevin Ryan's long-suffering girlfriend, who was loyal to him throughout the challenges of his work. They begin dating during Season 1 and marry during Season 4. In Season 6, she has their first child, a girl named Sarah. In Season 8, she gives birth to a son, Nicholas Javier.
Juliana Dever has been married to her on-screen husband, Seamus Dever, since 2006. She has also appeared on the television series 9-1-1, Scandal, and Criminal Minds.
Senator William H. Bracken (Jack Coleman)
William Bracken is a corrupt politician representing New York. He was the former Assistant District Attorney for New York and was later elected to the Senate. As he begins a possible run for President, Beckett learns that he is connected to her mother's murder, beginning a cat-and-mouse game to bring him to justice.
Jack Coleman is perhaps best known for playing Noah Bennett ("Horn Rimmed Glasses") on Heroes. He also played Steven Carrington on the classic series Dynasty and appeared on The Office, Burn Notice, and Kingdom Hospital.
Jackson Hunt (James Brolin)
Jackson Hunt (an alias) is an undercover CIA agent and Richard Castle's father. His real name is not known. He met and fell in love with Richard's mother Martha, but his work kept him from having a family. He didn't meet Richard until decades later but kept tabs on him and Martha from a distance over the years.
James Brolin is a legendary actor whose fame rose in the 1970s by starring in the films Westworld, Capricorn One, and The Amityville Horror. In the 1980s, he was the star of the series Hotel and later appeared in Traffic, Burlesque, The 33, and Lightyear. The Emmy-winning actor is the father of Oscar-nominated actor Josh Brolin (The Goonies, No Country for Old Men, Sicario, and Avengers: Endgame).
