He spans genres such as science fiction, horror and fantasy, sometimes within the same novel: a typical example of Simmons' ability to intermingle genres is Song of Kali (1985), winner of World Fantasy Award.He is also a respected author of mysteries and thrillers, some of which feature the continuing character Joe Kurtz.
Born in Peoria, Illinois, Simmons received an A.B. in English from Wabash College in 1970, and, in 1971, a Masters in Education from Washington University in St. Louis. He subsequently worked in elementary education until 1989.
He soon started to write short stories, although his career did not take off until 1982, when, through Harlan Ellison's help, his short story "The River Styx Runs Upstream" was published and awarded first prize in a Twilight Zone Magazine story competition. His first novel, Song of Kali, was released in 1985.
Summer of Night (1991) recounts the childhood of a group of pre-teens who band together in the 1960s to defeat a centuries-old evil that terrorizes their hometown of Elm Haven, Illinois. The novel, which was praised by Stephen King, is similar to King's It in its focus on small town life, the corruption of innocence, the return of an ancient evil, and the responsibility for others that emerges with the transition from youth to adulthood.
In the sequel to Summer of Night, A Winter Haunting, Dale Stewart (one of the first book's protagonists, and now an adult), revisits his boyhood home to come to grips with mysteries that have disrupted his adult life. Children of the Night, another loose sequel, features a much older Mike O'Rourke, now a Roman Catholic priest, who is sent on a mission to investigate bizarre events in a European city. Another Summer of Night character, Dale's younger brother, Lawrence Stewart, appears as a minor character in Simmons' thriller Darwin's Blade, while the adult Cordie Cooke appears in Fires of Eden.
Soon after Summer of Night, Simmons, who had written mostly horror fiction, began to focus on writing science fiction, although in 2007 he returned with a work of historical fiction and horror, The Terror. In 2009 he also wrote a book, Drood, based on the last years of Charles Dickens' life, those leading up to the writing of The Mystery of Edwin Drood, which Dickens had partially completed at the time of his death.  In 2013 Simmons will release The Abominable, a supernatural horrow adventure, set on the snowy peaks of Mount Everest.
Simmons became famous in 1989 for Hyperion, winner of Hugo and Locus Awards for the best science fiction novel. This novel deals with a space war, and is inspired in its structure by Boccaccio's Decameron and Chaucer's Canterbury Tales.
Many of his works have similarly strong ties with classic literature:
- Carrion Comfort derives its title and many of its themes from a poem by Gerard Manley Hopkins
- "Vanni Fucci Is Alive and Well and Living In Hell", a 1988 short story lampooning televangelists included in Prayers to Broken Stones, is about a brief return to earth by the title character, an inhabitant of Dante's Inferno
- The Hyperion Cantos take their titles from poems by the English Romantic, John Keats.
- The basic structure of Hyperion is taken from the Middle-English cycle of stories The Canterbury Tales. A varied group of individuals are on a pilgrimage to solicit a kind of demon-god called "the Shrike" on the planet "Hyperion" in a universe on the edge of the apocalypse. Each pilgrim tells his or her tale of why they are going to see the Shrike. The Fall of Hyperion is the conclusion to the story of the pilgrims rather than a stand-alone sequel. Hyperion and Fall of Hyperion are essentially one work in two volumes.
- The Hollow Man (1992) is influenced by Dante's Inferno and T. S. Eliot
- A short story from 1993, "The Great Lover", is inspired by the World War I War Poets.
- In The Fall of Hyperion, John Keats appears as one of the main characters, with references to characters in Forbidden Planet and The Time Machine.
- His Ilium/Olympos cycle is inspired by Homer's works. Both Shakespeare and Proust are mentioned as well.
- The character of Ada and her home Ardis Hall in the Ilium cycle are inspired by Vladimir Nabokov's novel Ada or Ardor, which was Nabokov's foray into the science fiction genre and alternate history.
- His collection of short stories, "Worlds Enough & Time", takes its name from the first line of the poem To His Coy Mistress by British poet Andrew Marvell: 'Had we but world enough, and time,'.
In January 2004, it was announced that the screenplay he wrote for his novels Ilium and Olympos would be made into a film by Digital Domain and Barnet Bain Films, with Simmons acting as executive producer.
In 2009, Scott Derrickson was set to direct "Hyperion Cantos" for Warner Bros. and GK Films, with Trevor Sands penning the script to blend the first two cantos "Hyperion" and "The Fall of Hyperion" into one film. In 2011, actor Bradley Cooper expressed interest in taking over the adaptation.
His novel Drood was set to be adapted into a movie by Guillermo del Toro for Universal Pictures. The adaptation, originally thought to begin filming in 2012, seems to be on hold.
- Hyperion (1989) – Hugo and Locus Awards winner, BSFA nominee, 1990; Arthur C. Clarke Award nominee, 1992
- The Fall of Hyperion (1990) – Nebula Award nominee, 1990; BSFA and Locus Awards winner, Hugo Award nominee, 1991;
- Endymion (1996) – Locus Award shortlist, 1997
- The Rise of Endymion (1997) – Locus Award winner, Hugo Award nominee 1998
- Ilium (2003) – Locus Award winner, Hugo Award nominee, 2004
- Olympos (2005) – Locus Award shortlist, 2006
- Hardcase (2001)
- Hard Freeze (2002)
- Hard as Nails (2003)
- Song of Kali (1985) – World Fantasy Award winner, 1986
- Carrion Comfort (1989) – Bram Stoker Award winner 1989; British Fantasy Award winner, World Fantasy Award nominee, 1990
- Phases of Gravity (1989)
- Entropy's Bed at Midnight (1990)
- Prayers to Broken Stones (1990, short story collection)
- Summer of Night (1991) – British Fantasy Award, 1992
- Summer Sketches (1992, short story collection)
- Children of the Night (1992) – Locus Award 1993 (Horror)
- Lovedeath (1993, short story collection)
- The Hollow Man (1992) – Locus Award nominee, 1993
- Fires of Eden (1994)
- The Crook Factory (1999)
- Darwin's Blade (2000)
- A Winter Haunting (2002) – Locus Award nominee, 2003
- Worlds Enough & Time (2002, short story collection)
- The Terror (2007)
- Muse of Fire (2008, novella)
- The Guiding Nose of Ulfänt Banderōz (2009, novella)
- Drood (2009)
- Black Hills (2010)
- Flashback (2011)
- The Abominable (2013)
Bram Stoker Award
- Best Collection (1992): Prayers to Broken Stones
- Best Novel (1990): Carrion Comfort
- Best Novellette (1994): "Dying in Bangkok"
- Best Short Story (1993): "This Year's Class Picture"
British Fantasy Society Award
- Best Novel (1990): Carrion Comfort
British Science Fiction Award
- Best Novel (1991): The Fall of Hyperion
- Best Novel (1990): Hyperion
International Horror Guild Award
- Best Novel (2003): A Winter Haunting
- Best Horror Novel (1990): Carrion Comfort
- Best Science Fiction Novel (1990): Hyperion
- Best Novelette (1991): "Entropy's Bed at Midnight"
- Best Science Fiction Novel (1991): The Fall of Hyperion
- Best Horror/Dark Fantasy Novel (1992): Summer of Night
- Best Horror/Dark Fantasy Novel (1993): Children of the Night
- Best Novelette (1994): "Dying in Bangkok"
- Best Horror/Dark Fantasy Novel (1995): Fires of Eden
- Best Science Fiction Novel (1998): The Rise of Endymion
- Best Novelette (2000): "Orphans of the Helix"
- Best Science Fiction Novel (2004): Ilium
Science Fiction Chronicle Reader Awards
- Best Foreign Novel (1995): Hyperion
- Best Novel (1996): The Fall of Hyperion (tied with Timelike Infinity by Stephen Baxter)
- Best Foreign Short Story (1999): "This Year's Class Picture"
World Fantasy Award
- Best Novel (1986): Song of Kali
- Best Short story (1993): "This Year's Class Picture"
Dan Simmons has been nominated on numerous occasions in a range of categories for his fiction, including the Arthur C. Clarke Award, Bram Stoker Award, British Fantasy Society Award, Hugo Award, Nebula Award, and World Fantasy Award.