In second grade, Seamus Heffernan wrote a story about a passenger plane crash-landing into the Atlantic Ocean, and his impressed teacher suggested he should become a writer someday. He has only occasionally regretted taking her seriously.

Today, he is the author of the neo-noir detective novels NAPALM HEARTS and TEN GRAND, the first two books in the acclaimed Thaddeus Grayle series. As a screenwriter, his work has earned him entry to the 2022 Stowe Story Lab and the 2022 Willamette Writers FilmLabTV. His short fiction has appeared in The Raspberry and Louden Singletree, and his story "With Special Guests" was a 2018 Screencraft semi-finalist.

Prior to his writing career he worked in education, journalism, marketing and politics, and earned an M.A. in criminology. Born in St. John’s, Newfoundland, he has called several places home, including a lengthy stint in London, England. He currently resides in Port Moody, British Columbia, with his partner Chelsey and his son James.