Keown started working in comics in 1986 drawing several series for Aircel Comics, including Samurai, Elflord, DragonRing (later DragonForce), and Warlock 5.
Keown moved to Marvel Comics in 1989, where he first worked on Nth Man: the Ultimate Ninja, before replacing Jeff Purves on The Incredible Hulk. Keown worked on Hulk with writer Peter David, creating one of the most memorable runs of the book.
He left in 1993, to start publishing his self-created Pitt at Image Comics. In 1995, publication of Pitt was moved over to Full Bleed Studios (Dale Keown's own company).
He gradually lost interest and began working for other companies once more, drawing The Darkness for Top Cow and teaming up with Peter David once more with Hulk: The End for Marvel. Keown also drew a crossover featuring The Darkness and the Hulk.
Keown drew many of the pictures for the Hulk memorabilia that was released to coincide with the 2003 Hulk movie.
As of September 2005 Keown has been working on a crossover of The Darkness and Pitt, to be written by Paul Jenkins, with a special preview book released in December 2006 and the full three-issue limited series debuting in 2009.
Keown is currently working on The Incredible Hulk and Hulk.