The Diplomat returns with a cast that doubles down on messy marriages, moral compromises, and geopolitical brinkmanship. Season 3 centers on Kate Wyler and Hal Wyler while pulling Allison Janney’s Grace Penn and Bradley Whitford’s Todd Penn into the eye of the storm, with Austin Dennison and others shaping the fallout. Below is a complete, source-based breakdown of The Diplomat cast we see in Season 3, plus how the finale (“Schrödinger’s Wife”) repositions every key player.

Top of the ticket: Kate & Hal

Keri Russell as Kate Wyler

Russell describes Kate and Hal’s combustible bond as “so fun,” calling it “such a strange thing that they can drive each other so crazy, but be so good for each other too.” She adds, “It’s amazing what happens at the end of that first episode” before the st

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