The illustrator described the opportunity as "a real privilege" and praised writer Paul Cornell, with whom he collaborates on the 'New 52' title.
"For every comic book artist, being exclusive to DC Entertainment is a real privilege. I am extra happy to be working with a master like Paul Cornell, and a team of metahumans (don't call them superheroes!) that is different from any other conventional group you can see in the industry.
"The fact they've decided to give me an exclusive shows their faith in me and my work - and when you see what happens in the next three issues, you will be absolutely blown away! Thanks to DC and to the readers, you're the absolute BEST!"
Stormwatch originated as a WildStorm title before being integrated into the core DC Universe alongside other titles from the imprint, including Grifter.
Cornell is also under an exclusivity contract with DC, having signed a two-year agreement in 2010.
Stormwatch #2 went on sale this week.