Marin Ireland

Ireland made her off-Broadway theatre debut in Nocturne (2001), a play written by Adam Rapp, which ran at the New York Theatre Workshop. She also appeared in the play during its run in the American Repertory Theatre New Stages presentation at the Hasty Pudding Theatre, Cambridge, Massachusetts in October 2000. Her other off-Broadway work includes Caryl Churchill's Far Away (2002) at the New York Theatre Workshop. She played the title role in Sabina (2005) by Willy Holtzman at Primary Stages.

Ireland was featured in the 2008 stage adaptation of The Beebo Brinker Chronicles, a series of lesbian pulp fiction novels by Ann Bannon. She made her Broadway theatre debut in Reasons to Be Pretty (2009). For this performance, she received a nomination for the Tony Award for Best Featured Actress in a Play, and won the Theatre World Award. She then appeared in After Miss Julie in a Roundabout Theatre Company presentation of a Donmar Warehouse production at the American Airlines Theatre in September through December 2009. Ireland in the New Group revival of A Lie of the Mind in February and March 2010.

Ireland's early film roles are the drama Rachel Getting Married (2008) and the comedy The Understudy (2008). In 2012, she played the female lead role in the Matt Ross debut film 28 Hotel Rooms. For playing Ellen Doyle in Glass Chin (2014), she earned a nomination for the Independent Spirit Award for Best Supporting Female. In November 2012, she starred in the title role of Marie Antoinette in the world premiere at the Yale Repertory Theatre. She starred in the Lincoln Center Theatre production of Abe Koogler's Kill Floor in 2015. She has also appeared in the films The Family Fang (2015), Hell or High Water (2016), Piercing (2018), The Miseducation of Cameron Post (2018), and The Irishman (2019).

In 2012, while working on a Wooster Group production of Troilus and Cressida in London, Ireland dated costar Scott Shepherd. During that period, the couple fought physically at home, with Ireland once appearing at rehearsals with a black eye. Ireland later expressed disappointment that the Wooster Group did not do more to support her, and has lobbied theater unions to create protocols for handling misconduct.

Ireland has gained prominence in television industry, notably for her roles as Julia in the Amazon series Sneaky Pete (2015–2019), Sissy in the Netflix series The Umbrella Academy (2020–2022), and Nora Brady in the Hulu post-apocalyptic drama series Y: The Last Man (2021). Her leading role in the horror film The Dark and the Wicked (2020) earned her awards from a number of film festivals.

Ireland has narrated several audiobooks, including bestsellers by Frederik Backman, Anthony Doerr, and Amor Towles. She was awarded an Audie Award for Best Female Narrator in 2020 for her recording of Nothing to See Here by Kevin Wilson.