'The Diplomat' Cast: Who Plays Who in the Netflix TV Series

Netflix's hit thriller series The Diplomat is a must-watch show for many reasons: the complex yet accessible political intrigue, the gorgeous scenery-porn from multiple European castles, and the nuanced marriage at its center between Ambassadors Kate and Hal Wyler. The cast is also stacked, with each season adding more familiar faces that will have TV fans copying the Leo-pointing meme, including stars of classic comedy series, sci-fi hits, and prestige dramas (and no, we don't just mean star Keri Russell).

With season 4 of The Diplomat streaming now, it's time to get reacquainted with the talented cast and their characters' many allegiances. Read on to learn who's who in The Diplomat cast. (Plus, if you need a refresher on The Diplomat season 3's ending, we've got you covered.)

Everything to Know About the Cast of 'The Diplomat' Season 4

Keri Russell as Kate Wyler

Kate Wyler is a well-regarded U.S. diplomat who is taken by surprise when she's suddenly diverted from her planned post in Afghanistan and appointed as the new U.S. Ambassador to the U.K. As she adjusts to the public-facing side of her new role (an aspect she is uncomfortable with), Kate has to balance a deadly conspiracy involving the U.S. and the U.K., a temperamental relationship with a new president, and her rocky (to put it mildly) marriage.

Keri Russell, 50, rose to fame with her breakthrough TV role on the ABC drama Felicity and went on to play Elizabeth Jennings on the Emmy-winning spy thriller The Americans. She also starred in films like Waitress, August Rush, Austenland, Extraordinary Measures, Star Wars Episode IX: The Rise of Skywalker, and Cocaine Bear. She's in a committed relationship with her The Americans co-star Matthew Rhys. (In a recent interview, Russell shared that she thinks marriage is "antiquated.") Russell and Rhys have one son together, while Russell shares two children with her ex-husband Shane Deary.

Rufus Sewell as Hal Wyler

Kate’s husband Hal is a charismatic, legendary diplomat and former ambassador. (He's also occasionally referred to as "Ambassador Wyler," to much confusion.) Though he begins the series unemployed after landing on the wrong side of the Secretary of State, he fills his time by applying his ruthless and manipulative methods to diplomatic relations, to the dismay of his wife. By season 3, he's ascended to the second most-powerful position in government.

Rufus Sewell, 58, is a British(!) TV and film veteran known for his roles in A Knight’s Tale, The Legend of Zorro, The Illusionist, The Holiday, Tristan & Isolde, Victoria, The Man in the High Castle, The Marvelous Mrs. Maisel, Judy, and Kaleidoscope, and the Netflix film Scoop. Next up, he's set to play the Bennett patriarch in Netflix's upcoming Pride and Prejudice series.

Rufus Sewell's Instagram: @rufus_sewell

Allison Janney as Grace Penn

U.S. Vice President Grace Penn travels to London in season 2 to meet her competition, Kate Wyler, A.K.A. the person who may replace her. After the season 2 finale, the pair are completely at odds...just in time for Grace to assume the presidency. As Grace struggles to balance her own instincts with honoring her late predecessor's agenda, she also faces sexism as the first female president.

Allison Janney, 66, is best known for playing White House press secretary C.J. Cregg on The West Wing; The Diplomat marks her reunion with creator Debora Cahn, a writer on the hit political series. Since then, Janney has won an Academy Award for 2017's I, Tonya, three Emmys for CBS' Mom and Showtime's Masters of Sex (joining her four awards for her work on The West Wing), and two Tony nominations for A View from the Bridge and 9 to 5.

Allison Janney's Instagram: @allisonbjanney

Bradley Whitford as Todd Penn

After two seasons of mentions, The Diplomat season 3 introduces Todd Penn, Grace Penn's husband. Viewers really get to know Todd in season 4, as the First Husband struggles with his wife's new position of power.

Bradley Whitford's casting in The Diplomat is a second West Wing reunion, with the former Josh Lyman, deputy chief of staff, reuniting with Cahn and Janney. The 67-year-old Emmy winner is a longtime television actor, also known for appearing in ER, The Mentalist, Transparent, Brooklyn Nine-Nine, and The Handmaid's Tale. In film, he has starred in dozens of movies, including The Sisterhood of the Traveling Pants, The Cabin in the Woods, Saving Mr. Banks, and Get Out.

Bradley Whitford's Instagram: @bradleywhitford

Ato Essandoh as Stuart Hayford

Stuart is the Deputy Chief of Mission (DCM) at the U.S. Embassy in London and Kate’s second-in-command, helping her adjust to the new role. In addition to his duties, he's been asked to judge whether Kate is Vice President-material, due to his experience as a campaign manager in DC. He's also been in a low-key relationship with Eidra.

Ato Essandoh, 54, is a New York native with a prolific résumé; his credits in films and series include Hitch, Chicago Med, Copper, Jason Bourne, Garden State, Blood Diamond, Girls, Vinyl, Altered Carbon, The Code, Elementary, Blue Bloods, and Reptile.

Ato Essandoh's Instagram: @atoessandoh

Ali Ahn as Eidra Park

Eidra is the Chief of the CIA Station in London and manages the very close and very complicated relationship between the CIA and MI6. Her responsibilities include relaying intelligence information to Kate’s team. She's initially suspicious of Kate but eventually warms up to her as the two women work together.

Ali Ahn, 45, is best known for her roles in the series Agatha All Along, Billions, The Breaks, Black Box, The Path, Raising Dion, and The Other Two, as well as the film Liberal Arts. She has been in a relationship with The Good Place's William Jackson Harper for over a decade.

Ali Ahn's Instagram: @aliahn

Nana Mensah as Billie Appiah

White House Chief of Staff Billie Appiah is an ambitious public servant and skilled fixer with a strong loyalty to the late President Rayburn (Michael McKean). She and Stuart used to run campaigns together, and she relies on his judgment for many things, including Kate’s political future.

Nana Mensah, 38, previously starred in the shows Presumed Innocent, The Chair, Bonding, 13 Reasons Why, New Amsterdam, An African City, and Orange Is the New Black, as well as the films After Yang and The King of Staten Island. She also directed and starred in 2021's Queen of Glory.

Nana Mensah's Instagram: @itsnanamensah

David Gyasi as Austin Dennison

Dennison is the British Foreign Secretary, overseeing U.K. foreign relations on behalf of Prime Minister Nicol Trowbridge. Weighed down by his struggle to rein in his brash (and potentially dangerous) head of government, he and Kate come to rely on each other as unexpected allies.

David Gyasi, 46, is a prolific actor best known for his roles in Interstellar, Carnival Row, Cloud Atlas, Annihilation, The Bastard Son & The Devil Himself, Maleficent: Mistress of Evil, Containment, and Troy: Fall of a City. He also voiced the Grey Cat in the special episode of Netflix's The Sandman.

David Gyasi's Instagram: @thedavidgyasi

Rory Kinnear as Nicol Trowbridge

U.K. Prime Minister Nicol Trowbridge is a bombastic, volatile leader who never questions his pro-war mentality (hence Dennison needing to keep him in line). After three seasons dealing with the U.K. and U.S.'s complicated alliance, season 4 sees Trowbridge make a shocking decision.

Rory Kinnear, 48, is a British actor and playwright best known for playing Bill Tanner in the James Bond films Quantum of Solace, Skyfall, Spectre, and No Time to Die. His credits include The Lord of the Rings: The Rings of Power, The Ministry of Ungentlemanly Warfare, Our Flag Means Death, and The Imitation Game. He also notably played another prime minister in the first-ever Black Mirror episode, "The National Anthem." (Fun fact: Kinnear's real-life spouse, actress Pandora Colin, plays Mrs. Lydia Trowbridge.)

Celia Imrie as Margaret Roylin

Meg Roylin is a well-known, shrewd Tory (Britain's conservative party) operative. She's Trowbridge's most influential advisor, whose competence is impressive— though she can be dangerous if you land on her bad side.

Celia Imrie, 74, is best known for appearing in the iconic Bridget Jones rom-com series, as well as playing Sam Fox's mother Phyllis in the acclaimed FX series Better Things. Her other notable projects include Nanny McPhee, Mamma Mia! Here We Go Again, the Best Exotic Marigold Hotel duology, and Netflix's cozy murder-mystery The Thursday Murder Club. Last year, she competed on the inaugural season of The Celebrity Traitors U.K.

Celia Imrie's Instagram: @celia.imrie

Penny Downie as Frances Munning

Frances is the resident manager of Winfield House, the historic London manor Kate and Hal live in during their time in the U.K.

She's portrayed by Penny Downie, 72, an Australian actress who played the Duchess of Gloucester in seasons 3 and 4 of The Crown. She also appeared in several acclaimed films and series, including Downton Abbey, Jackie, Invictus, Breathe, Crime and Punishment, and The House of Mirth.

Georgie Henley as Pensy

Winfield House assistant Pensy is played by Georgie Henley, a familiar face for fans of 2000s movies. The 31-year-old first rose to fame as a child actor playing Lucy in The Chronicles of Narnia films The Lion, the Witch, and the Wardrobe, Prince Caspian, and The Voyage of the Dawn Treader. She has since starred in films Perfect Sisters and The Sisterhood of the Night, as well as the STARZ series The Spanish Princess.

Georgie Henley's Instagram: @georgiehenley

Aidan Turner as Callum Ellis

In season 3, Kate meets Callum Ellis, a "bird watcher" who has ties to the British military. (So, a spy.) Though Kate's intrigued by the mystery man, he may remind you of a certain someone.

Aidan Turner, 43, is an Irish actor who rose to international fame as the dwarf Kili in The Hobbit film trilogy. He went on to star in two historical dramas, playing British soldier Ross Poldark in the BBC series Poldark, followed by Leonardo da Vinci in the Italian series Leonardo. He also currently stars alongside David Tennant and Alex Hassell in the Hulu series Rivals. (Fun fact: He's been married to We Were Liars star Caitlin FitzGerald since 2020.)

Miguel Sandoval as Miguel Ganon

Miguel Ganon is the U.S. Secretary of State. He's notably ambitious about his political career and disapproves when Kate goes rogue to get the job done. He is also not a fan of Hal.

Washington, D.C. native Miguel Sandoval, 74, has a decades-long career in TV and film and has appeared in several acclaimed films, including Clear and Present Danger, Jurassic Park, Do the Right Thing, and Jungle Fever. He's also known for his roles in the series Medium, Station 19, Bad Judge, Sharp Objects, Barry, This Fool, and Sugar.

Rosaline Elbay as Nora

Nora is the Vice President’s chief of staff. After the events of the season 2 finale, Nora finds herself much busier and right in the middle of Kate and Hal's arguments.

Rosaline Elbay, 35, is an Egyptian actress, writer, and advocate who studied archaeology at Oxford University before pursuing her dream of acting. She previously appeared in the Egyptian series Qabeel, Hulu's Ramy, and Netflix's Kaleidoscope, as well as the psychological thriller Jagged Mind.

Rosaline Elbay's Instagram: @rosaline.elbay

Jodie Whittaker as Bethan Vaughn

Season 4 of The Diplomat undergoes an overhaul of the show's British politicians. After Trowbridge resigns as prime minister, Bethan Vaughn steps into the role. Though Kate is excited at the thought of working with her, Vaughn inherits her predecessor's wariness of the Americans' idea of loyalty.

Jodie Whittaker, 44, is a British actress best known as the first-ever female actress to play the titular character in Doctor Who. Before leading the iconic sci-fi series from 2018 to 2022, Whittaker gained international acclaim with her roles in the crime series Broadchurch and the "Entire History of You" episode of Black Mirror. She also recently starred in the Netflix true-crime series Toxic Town.

Tracy Ifeachor as Thema

The Pitt alum Tracy Ifeachor makes a memorable cameo in The Diplomat season 3 finale as Thema, a special new friend of Dennison's. The 41-year-old British actress previously appeared in shows such as The Originals, Quantico, Mayflies, and the Netflix miniseries Treason, as well as the 2023 musical Wonka. She's next set to star alongside Jake Gyllenhaal and Phoebe Dynevor in the M. Night Shyamalan film Remain.

Tracy Ifeachor's Instagram: @tracyifeachor_