Cooper grew up the son of a wealthy businessman in Arcadia, California. His first forays into literature came early, focusing on imitations of Rimbaud, Verlaine, de Sade, and Baudelaire. As he began his teenage years, he wrote poetry and stories on scandalous and often extreme subjects. At the age of fifteen, he began to plan an ambitious novel cycle. This project, which took Cooper nearly twenty years to realize, would later become known as The George Miles Cycle. Cooper was an outsider and the leader of a group of poets, punk, stoner, and writers. After high school he attended Pasadena City College and, later, Pitzer College, where he had a poetry teacher who was to inspire him to pursue his writing outside of institutions of higher learning.
In 1976 Cooper went to England to become involved in the nascent punk scene. In the same year he began Little Caesar Magazine which included among other things an issue on and dedicated to Rimbaud. In 1978 with the success of the magazine, Cooper was able to found Little Caesar Press which featured the work of, among others, Brad Gooch, Amy Gerstler, Elaine Equi, Tim Dlugos, Joe Brainard, and Eileen Myles.
In 1979, Cooper published his first book of poetry, Idols, and became the director of programming at an alternative poetry space, Beyond Baroque, in Venice, California. He held that position for three years. Cooper's second book of poetry, Tenderness of the Wolves, published in 1982, was nominated for the Los Angeles Times Book Prize. In 1984, Cooper moved to New York City where he published his first book of fiction, a novella titled Safe, and began writing the cycle of five interconnected novels he had been planning since his mid-teens. In 1987 he moved to Amsterdam where he finished writing the first novel in the George Miles Cycle, Closer which later won the first Ferro-Grumley Award for gay literature.
While in Amsterdam he also wrote articles for different American magazines including Art in America, The Advocate, the Village Voice and others. He returned to New York in 1987 and began writing articles and reviews for Artforum, eventually becoming a contributing editor of the magazine. He began working on his next novel, Frisk. In the next few years Cooper worked on several different art and performance projects including co-curating an exhibit at LACE with Richard Hawkins entitled AGAINST NATURE: A Group Show of Work by Homosexual Men.
After moving to Los Angeles from New York in 1990, Cooper collaborated with a number of artists, including composer John Zorn, painter Lari Pittman, sculptors Jason Meadows and Nayland Blake, and others. For several years, he was a contributing editor and regular writer for the rock music magazine Spin. In 1994, he founded the "Little House on the Bowery" imprint for the independent publisher Akashic Books, which has published works by Travis Jeppesen, Richard Hell, Trinie Dalton, Benjamin Weissman, Derek McCormack and others. He completed his ten years of writing the George Miles Cycle with the novel Period in the year 2000. The cycle has now been translated into 17 foreign languages and is the subject of numerous academic studies. They include two volumes of critical essays devoted to the cycle: Enter at Your Own Risk (2004), edited by Leora Lev, and Dennis Cooper: Writing at the Edge (2008), edited by Paul Hegarty and Danny Kennedy. Since then he has written three novels: My Loose Thread, God Jr., and The Sluts (winner of the 2007 Prix Sade in France and the 2005 Lammy Award for best book of gay fiction).
Since the summer of 2005, Cooper has spent most of his time in Paris. While there, he has worked on his blog, which Cooper considers his current major artistic project, and has collaborated with the French theater director Gisele Vienne and composer Peter Rehberg on four works for the theater, I Apologize (2004), Un Belle Enfant Blonde (2005), Kindertotenlieder (2007), and a stage adaption of his novella Jerk (2008). These theater works have been highly acclaimed and continue to tour extensively in Europe, the UK, and Asia. While in France, Cooper finished a new book of poetry, The Weaklings, which was published in a limited edition by Fanzine Press in March 2008, a collection of short fiction titled Ugly Man (Harper Perennial, 2009), and Smothered in Hugs: Essays, Interviews, Feedback, and Obituaries (Harper Perennial, 2010).
As of late 2010, Cooper was completing his ninth novel, tentatively titled The Marbled Swarm. He recently played a small role in Christophe Honore's feature film Homme au Bain. 2011 will see the publication of two books by Cooper: an expanded paperback edition of his 2008 poetry collection The Weaklings (Alyson Books), and the reissue of his and the artist Keith Mayerson's 1997 graphic novel Horror Hospital Unplugged (Harper Perennial). In addition, This Is How You Will Disappear, Cooper's fifth theater work created in collaboration with the French director Gisele Vienne and the musicians and composers Peter Rehberg and Stephen O'Malley of the band Sunn0))) premiered at Festival de l'Avignon in July 2010 and is currently on tour in Europe and Asia.
In addition to their United States editions, Cooper's novels and books of poetry have been published in Sweden, Finland, Denmark, Norway, the Netherlands, France, Germany, Spain, Portugal, the United Kingdom, Italy, Croatia, Hungary, Israel, China, and Japan.