Peter Hubbard, executive editor at William Morrow & Co, said Pirsig's wife Wendy had confirmed the author's death at his home in Maine "after a period of failing health".
Pirsig was best known for his 1974 philosophical novel Zen and the Art of Motorcycle Maintenance.
The semi-autobiographical novel told the story of a father-son motorcycle trip across the western United States.
Pirsig claimed the book was rejected by 121 publishers
The book sold more than five million copies around the world but was originally rejected by more than 100 publishers.
The story was loosely based on a cross-country motorcycle trip that Pirsig took with his 11-year-old son, Christopher, and two friends, in 1968.
Pirsig was born in Minneapolis on 6 September 1928.
He released a second novel in 1991 - Lila: An Inquiry Into Morals - which picked up where Zen left off.
The follow-up book was nominated as a finalist for the Pulitzer Prize for Fiction in 1992.
Pirsig's novel was based on a motorcycle trip he took with his son
After his death was announced, fans of Pirsig's books took to Twitter to pay tribute to the author.
US radio host Glynn Washington said: "A long time ago, everyone kept telling me to read this book. Everyone was right. One love, Robert Pirsig."
"Here's to your next road trip across the heavens, my inspiration. RIP Robert Pirsig," wrote Mahesh Murthy.
Jamie Bourdreau tweeted: "As cliche as it sounds/is, Robert Pirsig shifted my paradigm as a young person struggling with adolescence. Thank you for your book."
Pirsig is survived by his wife Wendy and two children.