Olsen gained worldwide recognition for her portrayal of Wanda Maximoff / Scarlet Witch in the Marvel Cinematic Universe media franchise, including in Avengers: Age of Ultron (2015), Doctor Strange in the Multiverse of Madness (2022), and the miniseries WandaVision (2021).

She also starred as a widow in the drama series Sorry for Your Loss (2018–2019) and as Candy Montgomery in the miniseries Love & Death (2023), with the latter earning her another nomination for a Golden Globe Award.

[4][5] She is the younger sister of twin fashion designers Mary-Kate and Ashley Olsen, who became successful television and film actresses as children.

[20] Despite premiering at the Sundance Film Festival alongside Martha Marcy May Marlene, it was released in 2012,[21] during which she also starred in the thriller Red Lights and the comedy Liberal Arts.

[23] Later that year, she played Edie Parker, novelist Jack Kerouac's first wife and the author of the Beat Generation memoir You'll Be Okay, in the biographical drama Kill Your Darlings.

[35] She first appeared as the character in a post-credits scene of the 2014 film Captain America: The Winter Soldier, alongside Aaron Taylor-Johnson, who portrayed Maximoff's brother, Pietro.

[44][45][46] Vulture's David Edelstein found Olsen's "incongruously high-schoolish demeanor" in Wind River problematic,[47] while Peter Travers of Rolling Stone wrote that she gave a "major eye-opener of a performance" in Ingrid Goes West, deeming it "toxic perfection".

[49] Olsen executive produced and starred as a young widow named Leigh Shaw in the Facebook Watch web television series Sorry for Your Loss, which premiered in September 2018.

[57] Alongside Paul Bettany as Vision, Olsen played Maximoff again in the superhero miniseries WandaVision, which premiered on Disney+ in January 2021.

Olsen's performance received praise, with Owen Gleiberman of Variety writing that it "generates an operatic fire".

[64][65] Olsen starred as housewife Candy Montgomery in Love and Death (2023), an HBO Max limited series about a 1980 killing in Texas.

[67] Following the series, Olsen then starred in Azazel Jacobs' drama film His Three Daughters and the science fiction thriller The Assessment.

[1] Olsen says she became an atheist at the age of 13 because she believes "religion should be about community and having a place to go in prayer, not something that should determine women's freedoms.

[73] Olsen became engaged to musician Robbie Arnett, of the American band Milo Greene, in July 2019 after three years of dating.