Also in 1993, O'Nan was able to find a publisher for his second book, and first novel, Snow Angels—based on the story "Finding Amy" from In the Walled City—when the manuscript earned him the first Pirate's Alley Faulkner Prize for the Novel, awarded by the Pirate's Alley Faulkner Society of New Orleans. In 2007 Snow Angels was adapted for a film of the same title, directed by David Gordon Green, who also wrote the screenplay, and which starred Sam Rockwell and Kate Beckinsale. In 1995, his family and he moved to Avon, Connecticut. He was a writer-in-residence and taught creative writing at Trinity College in nearby Hartford until 1997. The research he did for his novel The Names of the Dead led to the creation of a class that studied Vietnam War memoirs as a form of literature, which he also initially taught. In 1996, Granta named him one of America's Best Young Novelists. In a 2002 article, "Finding Time to Write," he wrote: A Face in the Crowd is a novella by Stephen King and O'Nan, originally published as an e-book on August 21, 2012, as well as an audiobook, read by Craig Wasson. In 2015, O'Nan released a novel entitled West of Sunset, about the last days of writer F. Scott Fitzgerald as he moves out to Los Angeles after being ruined financially and experiencing health problems, after also his wife is put in an insane asylum. Filmmaker James Ponsoldt has been in negotiations to write and direct a film adaptation of the book, with actors like Tom Hanks, Emily Watson and Alicia Vikander currently being attached.
Nonfiction books
When he researched The Circus Fire, he advertised in The Hartford Courant and received many answers to his request for interviews with survivors of the Hartford Circus fire. In the spring of 2005 O'Nan spoke at the Lucy Robbins Welles Library in Newington, Connecticut, as the featured author in its One Book, 4 Towns program. In an article for Connecticut Magazine, when asked about , the book he co-authored with Stephen King, O'Nan replied, "I always tell my friends that the luckiest thing that ever happened to me was becoming a Red Sox fan."
Screenplays and other writing
In 2008, Lonely Road Books sold out its pre-orders for O'Nan's latest writing, a screenplay simply titled Poe. It is a dramatic retelling of the life of Edgar Allan Poe. The screenplay was released as a limited edition of 200 copies and as a lettered edition of 26 copies. It features a foreword by Roger Corman and frontispieces by Jill Bauman.
