Born in the Midwest of the United States, Grimly was drawn to the exciting and scary world of monsters and goblins. He was heavily inspired by classic horror films, comics, fine art, and writers such as Edgar Allan Poe, Edward Gorey, and H.P. Lovecraft. Grimly credits Jon J Muth as the sole reason he took up watercolor. "When I was young, I saw a copy of Moonshadow and wanted to do art like that. My work looks nothing like it, but that is why I went in that direction."  After graduating from college, where he studied art, Mr. Grimly moved to Los Angeles to broaden his experiences and opportunities. A couple of major studios had hired him to do concept work, and during his spare time he created a series of original miniature books which had the look and appeal of children's books, but the dark and twisted style only he could create. These books are now extremely rare and valuable. Although his intent was to work in the comic industry, this series of books landed him his first job illustrating children's books. This book, Monster Museum, and the ones that followed, defined a different style of children's books illustration which is entertaining enough for children to desire to read, yet adult enough for parents to enjoy as well. The success of these books garnered Mr. Grimly much respect within the industry and has led to his illustrations being seen in over a dozen books in only eight years. His ability has been used to recreate classics such as Edgar Allan Poe, Pinocchio, and The Legend of Sleepy Hollow as well as to invent characters in his Wicked Nursery Rhymes series and Little Jordan Ray's Muddy Spud.
In 2005, his inventiveness made its way into movies as he wrote, directed, and produced his first short film, "Cannibal Flesh Riot!" This film started as a joint endeavor by Grimly and his good friend Peter Sandorff, the guitarist for The Nekromantix, Schwartzwald Library and Mad Sin. Originally intended to be a comic which would have a score to accompany it, the story turned into a 35-minute short film consisting mostly of live action with segments of stop motion animation. Also, Sandorff created a band, Hola Ghost, in order to score the film and write its title track. The film was released and received high praise at film festivals and conventions worldwide. This talent to direct with such a clear and original vision has blossomed into the likelihood of future short films for Gris Grimly's Mad Creator Productions, as well as ventures in making music videos.
In the summer of 2008, Gris Grimly produced and directed a music video for the Texas based Hellbilly rock band, Ghoultown. This video, although produced on a shoestring budget, was filmed partially at the legendary Magic Castle in Hollywood, and it starred Cassandra Peterson as her cult persona, Elvira.
In 2013, Harper Collins released Grimly's graphic adaptation of Mary Shelley's Frankenstein. On NPR, in October 2013, Grimly discussed his personal connection with characters in the story, particularly Frankenstein's monster. In the interview he revealed that, at the age of five, he was seriously burned on his back and 80 percent of his skin. He recounted that he "grew up feeling kind of like a monster" and that attracted him to the Frankenstein story.
- As author and illustrator
- Where Madness Reigns: The Art of Gris Grimly, (Baby Tattoo, 2009)
- Gris Grimly's Wicked Nursery Rhymes trilogy (Baby Tattoo)
- Wicked Nursery Rhymes III
- Wicked Nursery Rhymes II (2006)
- Wicked Nursery Rhymes (2003)
- Little Jordan Ray's Muddy Spud (Baby Tattoo, 2005)
- As illustrator only
- A Study in Scarlet, by Arthur Conan Doyle (Balzer + Bray, 2015)
- Frankenstein, by Mary Shelley (Balzer + Bray, 2011)
- The Death of Yorik Mortwell, by Stephen Messer (Random House, 2011)
- Edgar Allan Poe's Tales of Death and Dementia (Simon & Schuster, 2009)
- Sipping Spiders Through a Straw: Campfire Songs for Monsters, by Kelly Dipucchio (Scholastic Press, 2008)
- The Dangerous Alphabet, by Neil Gaiman (Harper Collins, 2008)
- The Legend of Sleepy Hollow, by Washington Irving (Simon & Schuster, 2007)
- Santa Claws, by Laura Leuck (Chronicle, 2006)
- Grimericks, by Susan Pearson (Marshall Cavendish, 2005)
- Boris and Bella, by Carolyn Crimi (Harcourt, 2004)
- Edgar Allan Poe's Tales of Mystery and Madness (Simon & Schuster, 2004)
- Creature Carnival, by Marilyn Singer (Hyperion, 2004)
- Pinocchio, by Carlo Collodi (Tor Books, 2002)
- The Cockatrice Boys, by Joan Aiken (Tor Books, 2002)
- Monster Museum, by Marilyn Singer (Hyperion Press, 2001)
- Cannibal Flesh Riot (2006)
- The Craving (2007)
- Zeppo: El Exorcismo (2008)
- Wounded Embark of the Lovesick Mind (2009)
- "Cannibal Flesh Riot!" performed by Hola Ghost (2006)
- "Mistress of the Dark" performed by Ghoultown (2008)
- "Drawing Rock 'N' Roll And Sympathy Into Frankenstein's World". NPR. 2013-10-26.
- Gris Grimly Artwork on Exhibit at Hyaena Gallery
- Gris Grimly interview with Oddities Magazine
- Gris Grimly at The Gallery Zero
- On-Set Exclusive: We Follow the 'Wounded Embark of the Lovesick Mind' with Gris Grimly!
- New Poster and Update for Wounded Embark of the Lovesick Mind
- Artist Gris Grimly Touring with Baby Tattoo Books from Vegas to Kansas City
- Guillermo del Toro to Co-Direct New Darker Take on Pinocchio
- Cannibal Flesh Riot! Homepage