He is best known for his work at DC Comics including as the writer on the mainline Batman title, the Batman/Teenage Mutant Ninja Turtles trilogy, and Justice League Dark volume 2.

[3] After a brief stint in advertising, Tynion was asked by Scott Snyder to co-write the back-up features for the New 52 relaunch of Batman, beginning with the acclaimed "Night of the Owls" storyline.

[6] That same year, he released the GLAAD Media Award-nominated comic title Memetic with artist Eryk Donovan and Award-winning The Woods with Michael Dialynas at Boom Studios.

[12] In 2018, Tynion launched an acclaimed revival of the comic Justice League Dark,[13] which led into the Wonder Woman crossover storyline "The Witching Hour.

"[14] The following year, he launched the Eisner-winning and Harvey-nominated comic book mini-series Something is Killing the Children, which was later upgraded to an ongoing title due to high demand.

[20] In 2021, Tynion launched two Eisner Award-nominated comic titles–the first volume of the graphic novel series Wynd at Boom,[21] and the Eisner-winning The Nice House on the Lake at DC Black Label.

[23] That same year, Tynion and Boom announced a spin-off comic to Something is Killing the Children titled House of Slaughter, co-written with Tate Brombal (and later with Sam Johns),[24] which launched to record numbers.

[34] That November, it was reported that Tynion had partnered with Dark Horse Comics to release print versions of Tiny Onion's Substack books, as well as original stories.