Kitchen grew up in Wisconsin, attending William Horlick High School, Racine, where he cofounded and edited Klepto, an unofficial school paper, also contributing stories and illustrations to the paper. He continued this interest at the University of Wisconsin–Milwaukee, where in 1967 he cofounded and served as art director for the humor magazine Snide, also supplying cartoons. He also provided cartoons for the UWM Post. Originally a member of the ROTC on campus, Kitchen left ROTC, a decision he later attributed to an allergy to the wool uniform pants. He took classes in journalism and started frequenting a local avant-garde coffeehouse called the Avant Garde. He became opposed to the Vietnam War and joined the Socialist Labor Party of America.
Kitchen's founding of the Comic Book Legal Defense Fund occurred in 1986, after comic store manager Michael Correa was charged with possession and sale of obscene material. Since two of the works cited in the case as obscene were published by Kitchen Sink Press, Kitchen felt some responsibility for Correa's predicament, and so he set about raising funds for the defense of Correa, who saw his conviction overturned on appeal. Kitchen used surplus funds to incorporate the fund as a non-profitcharitable organization in 1990. Kitchen served as the fund's president from its inception until 2004, noting on his retirement from the board that "The challenges facing comics are different from when I founded the Fund … I think it's fitting that the generation directly facing these challenges … should be the ones standing up to them."
Art agency and art book
Kitchen Sink Press as a publisher went out of business in 1999, and Kitchen severed all ties with the company. Subsequent ventures have seen Kitchen establish himself as an art agent, handling the art sales of both Will Eisner and Harvey Kurtzman amongst others through his company Denis Kitchen Art Agency. He is a partner with Judith Hansen in Kitchen & Hansen Agency, LLC, which serves as a literary agency for Will Eisner's estate. Kitchen is also a partner in Kitchen, Lind & Associates which has served as agency and book packager for clients including The Estates of Harvey Kurtzman and Al Capp, Rebecca Guay, Howard Cruse, Eleanor Davis, Todd M. Hignite, Mark Fearing, and William Stout. In 2010, Dark Horse Comics released his long-awaited The Oddly Compelling Art of Denis Kitchen which serves as part-artbook and part-autobiography. In 2011, it would be nominated for an Eisner Award and a Harvey Award. It went on to win a 2011 American Graphic Design Award in the editorial category.
Kitchen Sink Books
In 2013, Dark Horse Comics announced it had established a joint venture imprint called Kitchen Sink Books. The imprint would be directed by Kitchen and business partner John Lind and focus on art books, historical collections and reprints and possibly original graphic novels. Dark Horse publisher Mike Richardson said of the imprint "I’m extremely pleased to be working with Denis and John on this new venture. My relationship with Denis goes back to the earliest days of Dark Horse and we’ve had a shared aesthetic with regard to comics from day one. With John, we have one of the best designer/editors in the business. I’m very much looking forward to the exciting projects that will result from this new imprint." The first book released under the new Kitchen imprint was The Best ofComix Book, a collection of work edited by Kitchen and Stan Lee in the mid-1970s. It was published as a large format hardcover in December 2013.