If there is one thing that Castle had going for it was the amazing Castle cast. What's a writer without his muse? That was the basic premise behind Castle, starring Nathan Fillion and Stana Katic. The 2009-2016 ABC crime-comedy-drama received praise and accolades during its time on the air. The show followed New York writer Rick Castle (Fillion) shadowing the exploits of NYPD Homicide Detective Kate Beckett (Katic).

With an ensemble cast of fellow detectives, police personnel, and civilians, the show had no shortage of fun and interesting characters. The series ended somewhat abruptly following Katic's departure from the show in 2016, so fans may be left wondering what happened to their favorite actors. Let's see what the cast of Castle has been up to since the series finale!

Arye Gross (Dr. Sidney Perlmutter)

The cantankerous and irritable Medical Examiner Ike Perlmutter may not have been on many episodes as part of the Castle cast, but he certainly left an impact. Not one to hide his dislike of Castle being a part of the NYPD, he appeared in and out of the show's eight seasons, typically for an episode or two. The actor behind Perlmutter, Arye Gross, has recently had cameos in shows like Designated Survivor and MacGyver.

Mostly, Gross has been busy pursuing an independent film career and a theater career since the show's cancelation. Gross appeared in the independent film The Lady Killers, as well as the film Nostalgia. He is a member of the Antaeus Theatre Company in Los Angeles, where he performed in Mrs. Warren's Profession and starred as the titular character in Uncle Vanya. Since Castle ended, Gross has shown up in several TV shows as well for single-episode appearances.

Ruben Santiago-Hudson (Captain Roy Montgomery)

Captain Roy Montgomery was the police captain of the 12th Precinct that housed Detectives Beckett, Esposito, and Ryan. A caring and passionate man, he routinely put his life on the line to protect his officers. This ultimately proved to be his demise. He was killed trying to stop the individuals responsible for having killed Beckett's mother in the season three finale, ending his role in the Castle cast.

Actor Ruben Santiago-Hudson would go on to appear on the TV Movie The Immortal Life of Henrietta Lacks and have minor appearances in the show Public Morals. Currently, Santiago-Hudson starred in 18 episodes of The Quad as Cecil Diamond and in Billions for eight episodes as Raul Gomez. More recently, he was in the main cast as a police officer for the 2022 CBS series, East New York.

Penny Johnson Jerald (Captain Victoria Gates)

After Captain Montgomery's death in season three, a new police Captain came to shake up the Castle cast. Enter Captain Victoria Gates, a strict no-nonsense police captain who shared little of her predecessor's sentimentality. She was hard and tough on her force, eventually earning their respect as a tough and capable officer.

Actress Penny Johnson Jerald has had a very successful career, and fans will know her from her prior work. She had multi-season roles in shows like ER, Star Trek: Deep Space Nine, and 24. After taking smaller projects since Castle's cancelation, Jerald has now returned to her sci-fi roots. She currently plays Dr. Claire Finn in The Orville. In 2019, she voiced Sarafina in the live-action version of The Lion King and will reprise the role in its sequel, Mufasa: The Lion King​​​​​.

Susan Sullivan (Martha Rodgers)

Few have the drama and gravitas that Martha Rodgers possesses in her day-to-day life. Martha is an accomplished actress and drama teacher at her own Martha Rodgers School of Acting. As the live-in mother of Rick Castle and grandmother of Alexis Castle in the Castle cast, Rodgers provides a whirlwind of excitement and drama whenever she appears on the show.

Her real-life actress, Susan Sullivan, is a film and television veteran, having been in the industry for over 50 years. She has appeared in new episodes of The Real O'Neils and Last Man Standing since Castle's cancelation. She starred in The Kominsky Method as Eileen, which is available for streaming on Netflix. Now 80, her last role was in 2020 in Last Man Standing.

Molly Quinn (Alexis Castle)

The bubbly and creative daughter of Rick Castle in the Castle cast, Alexis Castle morphs from a young teen to an independent woman over the course of the show. Being the only daughter of a single father meant being coddled, but Alexis proves to be wiser than her father on numerous occasions. She eventually goes on to become a private investigator, working alongside her father and stepmother.

The real Alexis Castle, Molly Quinn, is no less determined than her character. As a child actor, she got her start as the voice of Bloom on Winx Club before joining Castle. Afterward, Quinn would do some minor voice acting roles and online shorts. She appeared on The Fix on ABC, the horror movie Agnes, and she rejoined Nathan Fillion for two episodes of The Rookie in 2021 and 2023.

Tamala Jones (Dr. Lanie Parish)

Dr. Lanie Parish is the primary medical examiner that Castle and Beckett interact with on their cases in the Castle cast. Despite facing death and murder constantly, she has a warm and friendly demeanor, becoming close friends with Beckett. She has an on-again-off-again romance with Detective Esposito and eventually becomes a mentor to Alexis Castle.

Tamala Jones, the actress behind Laney, appeared in a majority of the show's seasons. Since then, she has had minor roles and cameos in shows like Rebel and Speechless. She had a small role in the film American Nightmare and appeared in the Taraji P. Henson film What Men Want. Starting in 2020, she appeared in a recurring role on 9-1-1: Lone Star as Detective Washington and had a couple of appearances on The Rookie.

Seamus Dever (Kevin Ryan)

Detective Kevin Ryan is a fellow 12th precinct detective alongside Detectives Beckett and his partner Detective Esposito. Esposito and Ryan are seen as a strong partnership and duo and often assist as a backup for Castle and Beckett. Ryan is a sharp, dedicated detective, despite being teased constantly by others for his love life with girlfriend-turned-wife Jenny throughout the show.

Ryan is played by actor Seamus Dever in the Castle cast, who before this was best known for his role as Dr. Devlin in General Hospital. Dever appeared as Trigon in Titans although that only lasted for three episodes. In 2019, he appeared alongside Nathon Fillion in an episode of The Rookie and also had a one-episode appearance on NCIS: Los Angeles.

Jon Huertas (Javier "Javi" Esposito)

The second half of the Ryan/Esposito team in the Castle cast, Detective Javier "Javi" Esposito is a tough and seasoned detective. Often quick with a sarcastic comment or joke, he quickly learns to take charge in cases and in the precinct. He eventually passes the sergeants exam, although we never see him become one prior to the show's cancellation.

Although actor Jon Huertas had been in numerous roles prior to Castle, the show appears to have been a turning point for him. After the show's cancelation in 2016, Huertas was quick to find his next long-term project. Huertas took on the role of Miguel Rivas in This is Us on NBC where he served as a main role character for the last five seasons.

Stana Katic (Kate Beckett)

One of the biggest characters in the Castle cast is Detective Kate Beckett. A no-nonsense, by-the-book detective, she initially detests working with Castle. However, the two eventually begin to work well together, becoming colleagues and eventually friends. Over time, the two fall in love and enter a relationship, getting married in season seven. The force behind Kate Beckett is Stana Katic, who has had no shortage of work prior to and after her time on the show.

When she's not working as a voice actor (Arkham City and Superman: Unbound), she is typically filming independent and foreign films. She has been prolific since the show's cancelation, appearing in and starring in films like The Rendezvous, Lost in Florence, and The Possession of Hannah Grace. Stana Katic's most recent TV show was Abstentia, where she starred as Agent Emily Byrne for three seasons.

Nathan Fillion (Rick Castle)

The titular star of the show, Rick Castle is a fictional best-selling crime author, often compared to Grisham and King. When he gets initially accused of murder, he instead aids Detective Beckett and solves the case with her. This would begin a long, fruitful partnership of him following her and writing down her exploits as inspiration for his next novel character.

Outside of the Castle cast, Nathan Fillion has been extremely prolific, voicing Green Lantern in various DC animated ventures and acting in roles like Firefly. After Castle, Fillion moved on to The Rookie, an ABC show where Fillion played an eager police rookie. The show is in its fifth season in 2022-23, and Fillion has appeared alongside several of his Castle co-stars on the show. On top of that, he also appeared in DC's The Suicide Squad and Hulu's M.O.D.O.K.