Watson (2025): Full cast list explored

Watson is a medical drama based on Arthur Conan Doyle's Sherlock Holmes stories. The show is written by Craig Sweeny and is jointly produced by Aaron Kaplan's Kapital Entertainment and CBS Studios.

The show's first episode premiered at MIPCOM Cannes on October 20, 2024, and went live on CBS on January 26, 2025. The show can now be streamed on Paramount+.

The show is set in Pittsburgh, it revolves around Dr. John Watson who works at Holmes Clinic, where he treats patients with rare and strange diseases.

The show has a diverse star cast, with Morris Chestnut playing Dr. Watson, Eve Harlow as Dr. Ingrid Derian, Inga Schlingmann as Dr. Sasha Lubbock, and Ritchie Coster as Mary Morstan.

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Main Cast of Watson (2025)

Morris Chestnut as Dr. John Watson

Morris on Watson Press Tour (Image via Instagram/@morrischestnutofficial)

Morris Chestnut plays the titular character Dr. John Watson, who after the loss of Sherlock Holmes, his best friend, channels his grief into running Holmes Institute in Pittsburgh. He uses techniques learned from Holmes to treat his patients with rare diseases. Apart from this, he also investigates the case of Holmes and his killer Moriarty's death. Chestnut previously was seen in Goliath season 2.

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Eve Harlow as Dr. Ingrid Derian

Source: (Image via Instagram/@eveharlow)

Harlow plays the neurologist Dr. Ingrid Derian in the show. She is known for her expertise in solving complex neurological cases and simultaneously helping her boss overcome Sherlock Holmes's death. She has a cold behavior and is not liked by her colleagues. Eve is known for her roles in Agents of S.H.E.I.L.D and The 100.

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Peter Mark Kendall as Stephens and Adam Croft

Peter (Centre) with Watson crew (Image via Instagram/@morrischestnutofficial) ource: (Image via Instagram/@ingaschlingmann)

Peter has a dual role in the show, as he plays the role of twin brothers Adam and Stephens. Adam is the one who attends Boston University and has a charming and outgoing personality. Stephens on the other hand is an emotionally withdrawn individual who went to Johns Hopkins University. Kendall is known for his roles in The Americans, Chicago Med, and Strange Angel to mention a few.

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Inga Schlingmann as Dr. Sasha Lubbock

Source: (Image via Instagram/@ingaschlingmann)

Schlingmann plays Doctor Sasha who is a rheumatologist and immunologist in the show. She is one of the trusted doctors of the clinic and manages her roles as a dual specialist well. Schlingmann is known for her role in So Help Me Todd.

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Ritchie Coster as Shinwell Johnson

Coster (Left) with Watson crew (Image via Instagram/@ingaschlingmann)

Shinwell Johnson, played by Coster, is a criminal and is John's loyal and close friend. He helps in running the administration of Holmes Clinic and is one who informs John about Sherlock Holmes's death in a flashback. Coster is known for his roles in The Dark Knight, Mistresses, and Tulsa King.

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Rochelle Aytes as Mary Mortsan

Source: (Image via Instagram/@rochelleaytes4real)

Rochelle Aytes portrayed Mary Mortsan, ex-wife of John and director of one of the local hospitals on the East Coast. Rochelle collaborates with Holmes Clinic on complex cases. Aytes returned to work with CBS after exiting the series FBI last year. She previously worked in White Chicks, Trick'r Treat, and Criminal Minds.

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Below is the supporting cast of the show:

• Tommy O'Brien as Zach
• Bethany Brown as Devin Chaplin
• Danny Mac as Nurse Beck
• Adrian Holmes as Detective Marcus Hayes
• Fiona Vroom as Dr. Lily Park
• Anjelica Bette Fellini as Erika Filipello
• Jean Zarzour as Mrs. Filipello
• Shannon Berry as Autumn Franco

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Overview of Episode 1 of Watson (2025)

The premier episode opens with a death sequence of Sherlock Holmes and Professor James Moriarty, in which Dr. Watson suffers a brain injury in an attempt to save Holmes. In the hospital post his recovery from the injury, John gets to know about Holmes Clinic in Pittsburgh, which was funded by Holmes for John.

After a few months, John moves to Pittsburgh to run the clinic and he starts building a team of doctors there. It's a clinic that solves odd and infrequent diseases. The first case of the clinic is of lady Erika Filipello, who is on the verge of dying from a fatal insomnia. John with his skills identifies that Erika is suffering from a genetic disorder involving biotinidase deficiency.

He works with Dr. Ingrid Derian and Dr. Sasha to solve this case. The episode sets the pilot for future episodes with John getting flashbacks of the death sequence and in the process realizing that Professor Moriarty might be alive.