According to Malone, he chose "Post Malone" as his stage name when he was 14 or 15. The name was rumored to be a reference to the professional basketball player Karl Malone,but Malone later explained that "Post" is his last name, and he used a "rap name generator" to get "Malone". At 16, using audio editor Audacity, Malone created his first mixtape, Young and After Them Riches. He showed it to some of his classmates at Grapevine High School. He was voted "Most Likely to Become Famous" by his classmates as a senior in high school. He worked at a Chicken Express as a teenager.
Malone later enrolled in Tarrant County College, but eventually dropped out. After leaving college, Malone moved to Los Angeles, California, with his longtime friend Jason Probst, a professional game streamer.
After moving to Los Angeles, Malone, Probst, and several other producers and artists formed the music group BLCKVRD and recorded music together. Several members of the group, including Malone, moved into a house in LA's San Fernando Valley together. While living in San Fernando Valley, Malone met record producers FKi 1st and Sauce Lord Rich, who formed the production team FKi, as well as Rex Kudo, who produced several of Malone's tracks, including "White Iverson". Malone recorded the song two days after writing it. The lyrics of "White Iverson" allude to Basketball Hall of Fame player Allen Iverson. In February 2015, upon completion, it was uploaded to Malone's SoundCloud account. On July 19, 2015, Malone released a music video for "White Iverson". The single received praise from Mac Miller and Wiz Khalifa. However, the song was notoriously mocked by Earl Sweatshirt.
After hitting one million views within a month of releasing "White Iverson", Malone quickly garnered attention from record labels. In August 2015, he signed a recording contract with Republic Records. Malone subsequently worked with a number of prominent rappers such as 50 Cent, Young Thug, and Kanye West, among others. In August 2015, he performed at Kylie Jenner's 18th birthday party, where he met Kanye West, who enjoyed his music, leading to him collaborating with Malone on his single "Fade" from his album The Life of Pablo (2016). Malone later began his friendship with Canadian singer and songwriter Justin Bieber, which led to Malone being an opening act for Bieber's Purpose World Tour (2016–17). On April 20, 2016, Malone premiered his new single, "Go Flex" on Zane Lowe's Beats 1 show.
On May 12, 2016, he released his first full-length project, a mixtape, titled August 26th, the title of which was a reference to the release date of his debut album. On June 9, 2016, Malone made his national television debut on Jimmy Kimmel Live!, performing "Go Flex".
In June 2016, XXL editor-in-chief Vanessa Satten revealed Malone was considered for XXL's "2016 Freshmen Class" magazine cover, but she was "told by his camp that he wasn't paying attention to hip hop so much. He was going in more of a rock/pop/country direction." However, Malone denied these claims, explaining that his latest mixtape as well as his upcoming album were both hip hop. In August 2016, Malone issued an apology for his album, Stoney, being late. It was available for pre-order on November 4, and was finally released on December 9. Malone later went on to call the album "mediocre",despite the success of the single "Congratulations" featuring Quavo, Malone's first top-ten song on the Billboard Hot 100, peaking at number eight. Stoney also featured the top 100 hits "I Fall Apart", and "Deja Vu", featuring Bieber, with the album later being certified double platinum by the RIAA in October 2017.
In February 2017, Malone revealed the title of his next project, Beerbongs & Bentleys, and was set to be released in December, before eventually being pushed back to 2018. In September, Malone released the first single from the album, "Rockstar", featuring 21 Savage. The song peaked at number one on the Billboard Hot 100 and held the spot for eight consecutive weeks, later prompting Rolling Stone to call him "one of the most popular musicians in the country" in 2017. In November, Malone released the official music video for "Rockstar", directed by Emil Nava.
On February 20, 2018, Malone previewed his new song with Ty Dolla Sign titled "Psycho." "Psycho" was released on February 23, 2018, and a tour with 21 Savage was announced. The song debuted at number 2 on the Billboard Hot 100, becoming Malone's third entry in the top 10. On April 5, 2018, Malone stated that Beerbongs & Bentleys will be released on April 27, 2018. The same day, he also premiered the song "Stay" during the Bud Lite Dive Bar show in Nashville. Upon release, Beerbongs & Bentleys broke the first day streaming records on Spotify, with 78.7 million streams worldwide. It debuted at number one on the Billboard 200 moving 461,000 album-equivalent units in its first week, with 153,000 coming from pure sales. The album was also certified platinum by the RIAA after four days and spawned three top 10 songs and six top 20 songs.
In an interview with Billboard in May 2018, Malone's manager announced that Malone was planning to start his own record label and film production company and Malone later won Top Rap Song at the Billboard Music Awards for "Rockstar" featuring 21 Savage. Malone confirmed in June 2018 that he was writing his third album, and confirmed that a festival would be taking place, organized by him, titled "Posty Fest", in Dallas, Texas on October 28. Malone promised a "blockbuster" lineup with headliners like rapper Travis Scott.
In August, Malone broke Michael Jackson's 34-year-old record for most weeks on Billboard's Top R&B and Hip-Hop Albums chart, with Stoney reaching its 77th week on the ranking compared to the 76 weeks that Thriller (1983) spent. A collaboration album with rapper Mac Miller was also teased in August 2018. During his appearance on The Tonight Show Starring Jimmy Fallon, he previewed his song "Sunflower", a collaboration with Swae Lee, from the soundtrack to the film Spider-Man: Into the Spider-Verse. In November 2018, it was confirmed Malone was recording his third album in his Utah home.
Malone was nominated for 4 awards at the 61st Grammy Awards for his album Beerbongs & Bentleys. Among the nominations were Album of the Year and Record of the Year. He performed with the Red Hot Chili Peppers at the awards show on February 10, 2019. In July 2019, Malone released the single "Goodbyes" featuring Young Thug, and also announced the Runaway Tour with Swae Lee as the opener. On August 5, Malone shared a snippet of an unreleased track "Circles" on YouTube. He then performed the song at his second annual Bud Light: Dive Bar concert and confirmed that the official song would be released the following week. That same day and on July 25, 2019, at Cheyenne Frontier Days he announced the album was finished. He released the song on August 30, 2019. He confirmed that his upcoming third studio album will be released on September 6, 2019. On August 26, 2019, Malone announced on Twitter that his third album is called Hollywood's Bleeding and would be released on September 6, 2019. The album debuted at number one on the Billboard 200, selling 489,000 album-equivalent units in its first week.