J-Milla was born in Darwin as Jacob Nichaloff,[1] and is of the Marranunggu people of the Litchfield Park area in the Northern Territory (NT).

[1] J-Milla started releasing rap videos on social media when he was around 18, which built a large following.

[2][4] In 2020, J-Milla pledged to donate the earnings from his single "Unlock the System" to the family of Kumanjayi Walker, an Aboriginal man who was killed during an arrest attempt.

[5] In November 2020, he performed at the TREATY festival as part of NAIDOC Week at Tandanya in Adelaide, along with Dem Mob, MLRN x RKM, and shared the MC duties with actor Natasha Wanganeen.

[7] He performed on the closing day of the Adelaide Festival in March 2021, at an event called "Hip Hop Finale", along with Ziggy Ramo, JK-47 and Jimblah.