Donny Cates was born in Dallas, Texas, but was raised in Garland, Texas. Cates has stated that during his childhood he learnt to read via comic books because of his father who was a big fan of the medium. He gratuated from the Garland High School and continued his studies in the Savannah College of Art & Design where he met two of his future collaborators - Tradd Moore and Geoff Shaw. He majored in sequential art but dropped out as he was accepted for a Marvel internship.
While interning, he received an advice from Mark Paniccia, an editor at Marvel, to leave the program and pursue a careen in writing his own comic books and he did. He left the Marvel internship and later on started his writing career at Dark Horse Comics where he wrote some short stories.
The writing career of Cates began at Dark Horse Comics where wrote a short story in their anthology series Dark Horse Presents. The first story from him was for issue #24 and came out in the second volume of the anthology in August 2013. The story was titled Hunter Quaid: Armageddon Outta Here and was done along with collaborator Eliot Rahal. The story was followed by another short story concentrating on the same character three issues later. The publisher was happy with the response for his writing and green lit some of his future projects, such as: Buzzkill, The Ghost Fleet and The Paybacks. He followed his writing gig at Dark Horse with a Star Trek story at IDW and later on started writing for Image where he published God Country. God Country was the book that attracted the Marvel editors who later on contacted him with an offer.
His first long-term Marvel works were runs on Doctor Strange and Thanos. After the success of these titles, Cates was given writing duties on Venom, where he was paired with artist and podcaster Ryan Stegman. This led to him penning multiple company-wide events, including Absolute Carnage and King In Black. In January 2020, Cates took over as the new writer of Thor with Nic Klein as artist. Later that year, he would reteam with God Country artist Geoff Shaw on the book Crossover. In June 2021, Cates and Stegman started their own production company entitled KLC Press,named after a Todd McFarlane quote ("Kids Love Chains"), with its first title set to be the book Vanish by Cates and Stegman. In November that same year, Cates became the new writer of Hulk, with Ryan Ottley joining as artist. In June 2022, it was announced Vanish would receive a physical release via Image Comics.