Harrier's role as Peter Parker's love interest Liz Allan in Spider-Man: Homecoming brought her international attention in 2017.

She gained further recognition for portraying civil rights activist Patrice Dumas in BlacKkKlansman (2018), receiving a Black Reel Award nomination.

[26][27] Additionally, she modeled for campaigns with companies such as Urban Outfitters, Macy's, American Eagle, Target, ALDO, Steve Madden, and L'Oréal.

[29] While studying at the William Esper Studio, her first acting job was the main role of Destiny Evans in the only season of the web series reboot of the American soap opera One Life to Live (2013).

[36][31] Errol Lewis from the Soap Opera Network wrote that Harrier "[has] nicely taken on the life of [her character]" and "the chemistry between [her and her on-screen boyfriend] is instantly there while leaving you wanting more".

[37] Harrier next guest starred as Amber in the television series Unforgettable (2014),[38][39] and made her film debut in The Last Five Years (2014) as a young woman who has an affair with Jamie, Jeremy Jordan's character.

[41][42][43] In 2015, she appeared in the film 4th Man Out,[44] and in her last year at William Esper she was cast in Codes of Conduct, an HBO miniseries pilot created by Steve McQueen.

[47] Harrier starred alongside Rowan Blanchard and Mahershala Ali in The Realest Real, a campaign film directed by Carrie Brownstein for luxury French fashion brand Kenzo in 2016.

[27] Spider-Man: Homecoming was Harrier's first blockbuster film, a box office success grossing over $880 million worldwide and receiving generally positive reviews.

[57][58] The film brought Harrier greater celebrity,[59][60] while her performance was met with mixed reviews; some critics praised her for avoiding the damsel in distress trope and breaking barriers as the first love interest of color,[61] and others were disappointed in her character's development and lack of screen time.

[64] Mark Hughes wrote for Forbes that Harrier is a "welcome change to the usual romantic interests in superhero film" and plays Liz as a "likable, sympathetic, type-A person".

[67] Harrier co-starred as Patrice Dumas, a civil rights activist, in the film BlacKkKlansman (2018) opposite John David Washington, Adam Driver, and Topher Grace.

[72][73] She also spoke with her father, who dealt with racism while living in South Side, and as the only black student at his boarding school in Michigan; his ancestors were slaves.

[96][97] In July 2020, Harrier played a young woman going through a breakup in the music video for "What's Love Got to Do with It", the remix version by Kygo of the original Tina Turner song.

[106] She lent her voice to the Netflix animated musical special Entergalactic, created by American rapper Kid Cudi as a visual companion to his album of the same name.

[107] In May 2022, Harrier was cast in a remake of Ron Shelton's 1992 film White Men Can't Jump for 20th Century Studios, which was released on May 13, 2023.