Moonheart, which I think of as his first full-on urban fantasy despite the secondary world sections, was definitely published before War, but to many of us at the time the latter was what I'd now call the genre codifier. At the time, I was reading everything in Terri Windling's fantasy imprint as it came out, because they were all Stuff I Really Liked, and War far and away was the best.

I liked de Lint's first half-dozen novels, but connected less and less with his writing and had stopped buying by the early 90s. (Being a poor grad student made that decision easier.)