It won’t be too long a wait for The Diplomat Season 4. Netflix shared updates on the Emmy-nominated drama’s upcoming season on August 17 that includes the premiere date, the first teaser trailer, and the first plot details.
The Diplomat stars Keri Russell and Rufus Sewell as a married couple with immense political power, Kate and Hal Wyler. Kate is the U.K. Ambassador, but she added Second Lady to her resume in Season 3 after Hal, also a former ambassador, unexpectedly became vice president of the United States, a job he was trying to snag for Kate in every season prior. Kate and Hal navigate how their relationship has a real-world impact, and how the high-stakes pressures of their careers both make and break their marriage, throughout the series.
“In Season 4 of The Diplomat, two marriages threaten to eat each other alive,” Netflix describes of the new season. “One catastrophic moment shatters the fragile peace Kate Wyler brokered between the U.S. and U.K., as well as the crumbling marriage she’s trying to save. While she fights to stem the bleeding, President Grace Penn [Allison Janney] and VP Hal Wyler’s conspiracy to steal Russia’s most powerful weapon hurtles the United States toward war. Kate and Todd [Bradley Whitford], at best an uneasy pair, unite to stop the Grace-Hal alliance from upending the balance of power abroad and at home.”
Here’s all the latest updates on The Diplomat Season 4. And here, you can get a refresher on The Diplomat Season 3 finale in our interviews with cast and creators.
Keri Russell as Kate Wyler, Rufus Sewell as Hal Wyler, Allison Janney as Grace Penn in ‘The Diplomat’ Season 4 Episode 1 (Netflix)
When does The Diplomat Season 4 premiere?
The Diplomat Season 4 comes out on Thursday, October 15, only on Netflix.
Is there a trailer for The Diplomat Season 4?
Check out the first official teaser in the video above.
Who is in The Diplomat Season 4 cast?
As previously announced, Nana Mensah will be a series regular in The Diplomat Season 4. The actor has played Billie Appiah, the White House chief of staff, since Season 1. Mensah joins Janney and Whitford, who have also been upped to series regulars in the fourth season, which started filming in fall 2025.
Mensah’s Billie started as chief of staff to President William Rayburn (Michael McKean). She was fiercely loyal to Rayburn and was one of the people trying to oust his Vice President Penn from her office earlier in the series. The plan was to replace Penn with Kate, but fate had other plans. Billie found herself serving as Penn’s chief of staff after the sudden death of Rayburn, who died while on the phone with Hal, as he delivered the distressing news about Penn’s involvement in the strike on the British ship in the Persian Gulf.
Clifton Prescod / Netflix
West Wing alums Janney and Whitford have been guest stars in the Emmy-nominated political drama until now. Janney first debuted in Season 2 as Vice President Grace Penn. Grace became president in the Season 2 finale, and Season 3 showed the aftermath. Whitford made his debut in the third season as Todd Penn, Grace’s husband, who is now the first gentleman. Grace and Todd’s marriage will be as important to Season 4 as Kate and Hal’s.
“This season is built on the foursome that is Kate, Hal, Grace, and Todd,” creator, showrunner, and executive producer Debora Cahn told Tudum. “They’re two couples strapped together in one car on a crumbling roller coaster. Each of them has a professional, public role that’s upending their ability to function as a married person. And there’s a change-partners thing that happens, where the growing bond between Grace and Hal creates a not-so-functional alliance between Kate and Todd.”
The Diplomat also stars David Gyasi, Rory Kinnear, Aidan Turner, Ali Ahn, and Ato Essandoh.
What happened in The Diplomat Season 3?
In Season 3 of The Diplomat, Ambassador Kate Wyler lived the particular nightmare that is getting what you want. She accused Penn of hatching a terrorist plot and admitted she was after the VP’s job. But now the president is dead, Kate’s husband Hal may have inadvertently killed him, and Penn is the leader of the free world. None of this slowed Hal’s campaign to land Kate the vice presidency, but Penn chose him as her VP instead. Kate stepped into a role she never wanted as second lady, with a freedom she never expected, an increasingly complicated friendship with Foreign Secretary Austin Dennison (Gyasi), and an unnerving bond with first gentleman Todd.
The series is created by showrunner/executive producer Cahn and is executive produced by Russell, Janice Williams, and Alex Graves.
The Diplomat, Season 4 Premiere, Thursday, October 15, Netflix