‘The Diplomat’: Allison Janney & Bradley Whitford Upped to Series Regulars for Season 4

Allison Janney and Bradley Whitford will be series regulars in The Diplomat Season 4. This news comes as Netflix prepares to release The Diplomat Season 3 in October.

The West Wing alums 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 the aftermath of her ascension will be seen in the Season 3 premiere. Whitford makes his debut in the third season as Todd Penn, Grace’s husband, who is now the first gentleman.

Production on Season 4 is set to begin this fall, according to Variety.

Ahead of The Diplomat Season 3 premiere, here’s everything we know about The Diplomat Season 4. (Get an exclusive early look into The Diplomat Season 3 in our 2025 Fall Preview.)

Has The Diplomat been renewed for Season 4?

Yes! The Diplomat was renewed for Season 4 on May 12. Season 3 consists of eight episodes.

When does The Diplomat Season 3 premiere?

The Diplomat Season 3 comes out in full on Thursday, October 16.

In Season 3 of The Diplomat, Ambassador Kate Wyler (Keri Russell) lives the particular nightmare that is getting what you want. She just accused Vice President Grace Penn (Janney) of hatching a terrorist plot and admitted she’s after the VP’s job. But now the President is dead, Kate’s husband Hal (Rufus Sewell) may have inadvertently killed him, and Grace Penn is the leader of the free world. None of this slows Hal’s campaign to land Kate the vice presidency. Kate steps into a role she never wanted, with a freedom she never expected, an increasingly complicated friendship with Foreign Secretary Austin Dennison (David Gyasi), and an unnerving bond with First Gentleman Todd Penn (Whitford).

“Everything we learned about Grace Penn at the end of Season 2 makes the relationship between the U.S. and the U.K. a lot more complicated going forward now that she’s president,” creator/executive producer Deborah Cahn told TV Insider. “Getting rid of her is not really viable in the same way…or maybe it is.”

Keri Russell as Kate Wyler, Rufus Sewell as Hal Wyler in The Diplomat Season 3 Episode 5 (Liam Daniel / Netflix)

Who is in The Diplomat cast?

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In addition to Russell, Sewell, Janney, Whitford, and Gyasi, The Diplomat stars Ali Ahn, Rory Kinnear, Ato Essandoh, and Nana Mensah. Rivals star Aidan Turner is also in Season 3 in a recurring role.

The series is created by showrunner/executive producer Cahn and is executive produced by Russell, Janice Williams, and Alex Graves.

When does The Diplomat Season 4 premiere?

The Diplomat Season 4 starts filming this fall. A release date will be announced at a later time.

The Diplomat, Season 3 Premiere, Thursday, October 16, Netflix