The selling out of the 4,000 print-run inspired him further, and in 1970 he founded Kitchen Sink Press (initially as an artists' cooperative)[3][4] and launched the Milwaukee-based underground newspaper The Bugle-American, with Jim Mitchell and others.

[7] In addition to Milwaukee artists like himself, Mitchell, Bruce Walthers, Don Glassford, and Wendel Pugh, Kitchen began to publish works by such cartoonists as Howard Cruse, Trina Robbins and S. Clay Wilson (as well as taking over the publishing duties of Bijou Funnies from 1970 to 1973), and he soon expanded his operations, launching Krupp Comic Works, a parent organization into which he placed ownership of Kitchen Sink Press and through which he also launched such diverse ventures as a record company and a commercial art studio.

Other titles launched by Kitchen Sink Press in this period, but later continued by other publishers, include Howard Cruse's Gay Comix, Don Simpson's Megaton Man, and Reed Waller and Kate Worley's Omaha the Cat Dancer.

Kitchen launched a second volume of The Spirit reprints in 1983, with a smaller page count and in standard comic book format.

Continuing their practice of collecting comic strips, in the 1990s Kitchen Sink reprinted volumes of Alley Oop, Flash Gordon, and Krazy Kat.

Original titles published by Kitchen Sink in the 1990s include Grateful Dead Comix (9 total issues, 1991–1993), editor Diane Noomin's Twisted Sisters limited series, (1994), Death Rattle vol.

Kitchen Sink also launched Charles Burns' Black Hole, which was later republished and augmented by Fantagraphics Books.

In 1993, Kitchen moved operations from Princeton, Wisconsin, to Northampton, Massachusetts, in a controversial – and ultimately disastrous – merger with Tundra Publishing.

Dark Horse editor Philip Simon commented on unannounced projects saying "everything [Denis and John] are bringing to the table is going to be historically important".