Mill will serve as president of the now Roc-Nation backed Dream Chasers, oversee the label and sign artists. The rapper also plans on opening a recording studio for his artists.
Dream Chasers was previously set up as a label imprint under Rick Ross's Maybach Music Group in 2012.
Mill posted on Twitter Wednesday a photo of himself signing papers next to Jay-Z. He captioned the photo by asking artists to send him links to their music.
"I think the time is now," Mill said to Rolling Stone about leading his own label. "I'm 32-years-old, I'm in a nice spot in the music business and I think it's time for me to focus on growing artists because that's what I love to do. I love to spend time on helping artists grow, and I think it's time for me to dive in, business-wise."
Mill and Jay-Z previously teamed up in January to help create the REFORM alliance, an organization that fights for criminal justice reform.
Jay-Z also appeared on Mill's latest album Championships, which topped the U.S. album charts in November.