[5] The brand eventually became popular overseas, with Mainframe glasses being worn by G-Dragon, Jennifer Lopez, Nicki Minaj, and Amber Rose and appearing in Vogue Korea, though she soon stopped making them due to not being paid for her designs.

[13] After appearing in a short film for a friend, she got the lead role in The Godmother, a scrapped biopic about Colombian drug lord Griselda Blanco, in 2015.

[18] Demie gained attention with her supporting role in the 2018 film Mid90s, written and directed by Jonah Hill, as Esmee, the protagonist's love interest.

[5] Although Demie had planned to take a break from acting to pursue her music career, she was impressed by the script for the series and decided to audition for it.

[21][1][22] Demie went on to star in the 2019 film Waves as Alexis, a teenager who is impregnated by her boyfriend, a popular but troubled high school wrestler played by Kelvin Harrison Jr.[8][23][24] She watched videos about codependency and drew on her own experience with an emotionally abusive relationship between her and a high school boyfriend, which she described as "very codependent", as the basis for the film's relationship.

[25][3] She also appeared in the comedy-drama film Mainstream in 2020 as Isabelle Roberts, a game show audience member, and made a cameo in The Neighbourhood's video for their 2020 song "Stargazing".

[26][27][28] In Nineteen on Fire, a 2021 short film written and directed by Ryan Simpkins, Demie played a drug dealer.