After making her acting debut in the crime film Blow (2001), Roberts gained recognition for her lead role as Addie Singer on the Nickelodeon television teen sitcom Unfabulous (2004–2007).

She went on to appear in numerous films including Aquamarine (2006), Nancy Drew (2007), Wild Child (2008), Hotel for Dogs (2009), Valentine's Day (2010), It's Kind of a Funny Story (2010), and The Art of Getting By (2011).

She has since appeared in The Blackcoat's Daughter (2015), Nerve (2016), Who We Are Now (2017), Paradise Hills (2019), Holidate (2020), and the Marvel superhero film Madame Web (2024).

That year, she also had a role in Leif Tilden's 10-minute short bigLove, and was an uncredited extra in some scenes featuring her aunt Julia Roberts in America's Sweethearts.

[11] Roberts went on to appear in smaller roles in two family films: in 2002's Grand Champion, as the sister of the main character Buddy (Jacob Fisher); and in 2006's Spymate, as the daughter of former secret agent Mike Muggins (Chris Potter), who tries to rescue her with the help of a spy monkey.

Also in 2004 at age 13, Roberts guest starred in an episode of the Nickelodeon series Drake & Josh titled "Honor Council".

The album includes several original songs (among them "Dummy" and "I Wanna Be", both of which were also released as music videos, "I Have Arrived" and "This Is Me", which was co-written by Roberts), as well as some of Addie's songs from the first season, including "Punch Rocker" and "New Shoes" (both from the episode "The Party"), "94 Weeks (Metal Mouth Freak)" (from "The Bar Mitzvah") and "Mexican Wrestler" (which had previously appeared on Jill Sobule's 2000 album Pink Pearl and in the episode "The 66th Day" from Unfabulous).

"[28] In 2008, Roberts starred as the lead in the film Wild Child,[29] about a rebellious teen from Malibu, California, sent to a boarding school in England.

[37][38] Roberts next appeared in the 2012 film Celeste and Jesse Forever, parodying pop stars such as Kesha with her performance as Riley Banks, an incurious blonde singer.

[39] 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.

Roberts co-starred with John Cusack and Evan Peters in the comedy-drama film Adult World, released on April 18, 2013.

[44] In the next month, she guest starred as Amanda Barrington in the animated sitcom Family Guy, in the episode "No Country Club for Old Men".

[46] 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.

[49] She then portrayed Maggie Esmerelda, a con artist posing as a fortune teller, in American Horror Story: Freak Show.

[50] In 2015, Roberts starred alongside Palo Alto co-star Nat Wolff in Ashby, portraying the supporting role of Eloise.

[52][53] Roberts next appeared in the horror film The Blackcoat's Daughter (also known by its original title February) alongside Kiernan Shipka.

[54] Roberts played the lead character Chanel Oberlin on Fox's comedy horror series Scream Queens, alongside Jamie Lee Curtis and Lea Michele.

[62] Later, Roberts returned to American Horror Story, guest starring as newscast reporter Serena Belinda, in its seventh season, Cult, in the episode "11/9".

[63] In March 2018, it was announced that Roberts was set to star in Anya's Ghost, an upcoming supernatural comedy film based on the award-winning graphic novel of the same name, written by Vera Brosgol and published in 2011.

[65][66][67] She next appeared in American Horror Story: Apocalypse, where she reprised her role of Madison Montgomery for the crossover season, returning to the main cast.

[68] On October 8, 2018, it was announced that Roberts had joined the cast of the animated musical comedy film UglyDolls, voicing the character Wedgehead.

[72][73] From September through November 2019, Roberts starred in the ninth season of American Horror Story, subtitled 1984, portraying Brooke Thompson.

[83] In April 2021, Roberts was cast to star alongside Thomas Mann[84] and Lewis Tan in the romantic comedy About Fate, directed by Marius Balčiūnas-Weisberg.

[88] Roberts appeared on the March 2022 cover of Tatler, with a photoshoot conducted at the Chateau Marmont in The Hamptons, a locale she has visited since her mother moved there.

[92][93] Roberts is also slated to both produce and star in Space Cadet, a romantic comedy film set to be exclusively released on Prime Video.

Through the platform, Roberts has recommended a variety of books including Octavia E Butler's Fledgling, Lisa Taddeo's Animal, Ariel Levy's The Rules Do Not Apply, The Impossible Lives of Greta Wells by Andrew Sean Greer, Eileen Myles' Chelsea Girls and When Watched by Leopoldine Core, among others.

[98] She has appeared multiple times as part of Teen Vogue's Best Dressed list, including in June 2007, September 2008, December 2008, and February 2009.

[100] Roberts has been involved in various charitable endeavors and philanthropic activities, focusing on children's welfare, environmental advocacy, women's rights, and public health awareness.

[101] More recently, in November 2023, Roberts was involved in St. Jude's Giving Tuesday event, where she led a celebrity unboxing segment.

[103][104] She collaborated with Free People Movement for a Thanksgiving Day 2023 campaign, focused on performing acts of kindness and assisting those in need, committing to donate all net proceeds to Girls Inc.[103] In September 2011 Roberts began attending Sarah Lawrence College, but by January 2012 had put her studies on hold to concentrate on work commitments.