She was a radio personality and singer in Denmark who performed with a group called Mik that sang at the World’s Fair in New York in 1964.

[29] In 2013, Stenberg began performing on the violin and singing harmonies at Los Angeles venues with singer-songwriter Zander Hawley.

[40] In 2018, she played the lead role of Starr Carter in the contemporary drama The Hate U Give, based on the novel of the same name, which is about the Black Lives Matter movement.

Peter Travers of Rolling Stone wrote: "It is impossible to over-praise Stenberg's incandescent performance, a gathering storm that grows in ferocity and feeling with each scene.

"[41] The film's director, George Tillman Jr., said that "She has this ability to make you feel like you're seeing the real deal, which comes from a level of dedication to the material that's rare at any age.

[43][44] In 2019, Stenberg portrayed Elizabeth Eckford, a 15-year-old girl who in 1957 was among a group of nine Black students who were initially prevented from entering a racially segregated high school in Little Rock, Arkansas during a segment on the television show Drunk History (2019).

[47] In August 2020, she was cast as Alana Beck in Stephen Chbosky's film adaptation of the Broadway musical Dear Evan Hansen.

She also collaborated with the show's composers, Pasek and Paul, on "The Anonymous Ones", a new song written specifically for her character, whose role was expanded upon from the stage version.

[49][50] On August 28, 2024, she shared via Instagram Stories that the cancellation of the show was "not a huge shock to [her]" due to the "hyper-conservative bigotry and vitriol, prejudice, hatred and hateful language" it received from Star Wars fans.

[57] Her video "Don't Cash Crop My Cornrows" admonished Kylie Jenner for adopting the traditionally African-American hairstyle.

[59] In October 2023, Stenberg signed the Artists4Ceasefire open letter to Joe Biden, President of the United States, calling for a ceasefire of the Israeli bombardment of Gaza.

Also in 2015, she released the video "Don't Cash Crop My Cornrows", which admonished Kylie Jenner for adopting the traditionally African-American hairstyle.

The track references a viral 2018 interview she had with The Daily Show's Trevor Noah, in which Stenberg raps "white people crying actually was the goal" of The Hate U Give, a film she stars in about the aftermath of a Black teenager's murder by a police officer.

[77][78] On October 6, 2018, Teen Vogue published an op-ed Stenberg had written for the magazine, in which she shared that she experienced two separate counts of sexual assault.

[79] From early 2018 to late 2018, Stenberg dated singer Mikaela Mullaney Straus, better known by her stage name King Princess.

[80] In a July 2017 interview, Stenberg said she had stopped using a smartphone, believing that such devices and social media can have a negative effect on mental health.