Born in Plantation, Florida, Onfroy spent most of his childhood in Lauderhill. He began writing music after being released from a youth correction center and released his first song on SoundCloud in June 2013, titled "News/Flock". He was a popular figure in SoundCloud rap, a trap scene that takes elements of lo-fi music and harsh 808s. Well known for his "depressing, and at times devastating" music that brought attention to mental health, Onfroy employed styles and techniques that were unconventional in hip hop during his career, such as distortion and heavy guitar-backed instrumentals drawing inspiration from third-wave emo.
Onfroy released his debut album, 17, on August 25, 2017. The album debuted at No. 2 on the US Billboard 200, selling 86,000 album-equivalent units first week. The album received a positive response from critics, some of which lauded the album for its personal narratives and diverse musical style. Onfroy's second album, ?, was released on March 16, 2018. It debuted at number one on the Billboard 200, with its singles "Sad!" and "Changes" peaking at numbers 1 and 18 on the Billboard Hot 100 respectively. The album was certified Gold by the RIAA on June 26, 2018.
Onfroy was shot and killed in an armed robbery after leaving a motorcycle dealership in Deerfield Beach, Florida, on June 18, 2018. In the week following his murder, Onfroy's highest-charting single, "Sad!", went from 52nd to 1st on the Billboard Hot 100, making Onfroy the first artist to top the Hot 100 posthumously in a lead role since The Notorious B.I.G., with "Mo Money Mo Problems", in 1997.
Onfroy left behind what Rolling Stone called "a huge musical footprint" due to his impact on his young fanbase and his popularity during his career.