Roberts was born in Rhinebeck, New York, to Kelly Cunningham and actor Eric Roberts. Her parents separated when she was a baby. Through her father's marriage, she is the stepdaughter of Eliza Roberts and step-granddaughter of David Rayfiel and Lila Garrett. Through her mother's marriage, she is the stepdaughter of musician Kelly Nickels.

On February 7, 2013, The Hollywood Reporter confirmed that Roberts had been cast to star in a pilot for Fox called Delirium, based on the Lauren Oliver novels. She portrayed Lena Haloway, the protagonist, but Fox decided not to pick up the show. Roberts then starred in the comedy film We're the Millers, alongside Jennifer Aniston and Jason Sudeikis. It was released on August 7, 2013. The film received mixed reviews from critics and was a financial success, grossing over $269 million against a budget of $37 million. She next appeared in season three of the FX horror anthology series American Horror Story, called American Horror Story: Coven, from late 2013 through January 2014. Roberts portrayed a self-involved party girl named Madison Montgomery, who also happens to be a telekinetic witch. She then portrayed Maggie Esmerelda, a con artist posing as a fortune teller, in American Horror Story: Freak Show.  Roberts played the lead role in Gia Coppola's directorial debut, Palo Alto, based on James Franco's short story collection of the same name. The film was released in May 2014 to generally positive reviews, with particular praise for Roberts' performance. Tom Shone of The Guardian and Ian Freer of Empire both called her the "standout" of the film, with Freer praising her performance for being "heartbreaking as she suggests longings and anxieties without over-hyping it. Much like the film itself." Roberts then starred alongside Palo Alto co-star Nat Wolff in Ashby, portraying the supporting role of Eloise. The film had its world premiere at the Tribeca Film Festival on April 19, 2015, and was released on September 25, in a limited release and through video on demand.  Roberts next appeared in the horror film The Blackcoat's Daughter (also known by its original title February) alongside Kiernan Shipka. Directed by Osgood Perkins, the film premiered at the 2015 Toronto International Film Festival. Roberts plays the lead character Chanel Oberlin on the first season of Fox's horror comedy series Scream Queens, alongside Jamie Lee Curtis and Lea Michele. The series was created by American Horror Story producers Ryan Murphy and Brad Falchuk, with Glee producer Ian Brennan. She reprised this role in the second season of Scream Queens the following year. It was later cancelled after two seasons. In 2016, Roberts starred alongside Dave Franco in Lionsgate's adaptation of the young-adult novel Nerve.  In June 2016, the Human Rights Campaign released a video in tribute to the victims of the 2016 Orlando gay nightclub shooting; in the video, Roberts and others told the stories of the people killed there.  On August 1, 2017, Ryan Murphy announced Roberts' return to American Horror Story, in its seventh season, Cult, via his personal Instagram account.

Who did she play ?
Maggie Esmerelda, a con artist posing as a fortune teller, in American Horror Story: Freak Show.