After he left college, Malone moved from Dallas, Texas to Los Angeles, California, with his longtime friend Jason Stokes. He later participated in a music group, called BLKCVRD, with Jason Stokes and Billie Gvtes, among others. He met 1st and Rich from FKi Music, who helped Malone produce several tracks, one of which is title "White Iverson". Malone recorded the song two days after he wrote it. It made him think that with that name of the song, after getting his hair braided, that it made looked like "White Iverson" (which is a reference to the professional basketball player Allen Iverson). In February 2015, upon the completion, it was uploaded to Post's SoundCloud account. Post Malone released a music video for "White Iverson" on July 19, 2015, which has received over 163 million views since its initial release. After the initial hype of "White Iverson", Post released several other popular singles to his SoundCloud; including "Too Young", "What's Up" and "Tear$", all of which saw a similar level of popularity to the breakout hit. These songs quickly gained him attention from record labels, after plays of over a million in one month each time that it upload. In August 2015, he secured a recording contract with Republic Records.

Since his breakthrough hit, Malone began working with a number of prominent rappers, such as 50 Cent, Young Thug and Kanye West. Malone also began a friendship with Canadian singer Justin Bieber, which led to Malone opening for Bieber on his Purpose World Tour. 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. On June 9, 2016 Malone made his national television debut on Jimmy Kimmel Live!, performing "Go Flex". In June, XXL editor-in chief Vanessa Satten, revealed Post Malone was considered for XXL's "2016 Freshmen Class" magazine cover, however 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 a couple days later, saying: "My love of music should never be questioned... I shouldn't be chastised in whichever way I see fit." He then went on to explain that his latest mixtape as well as his upcoming album are both hip-hop: "I have a hip-hop album coming out in August... I made a HIP HOP mixtape promoting my HIP HOP album