Thom graduated from Butler University in 1960 with a BA in Journalism after serving in the United States Marine Corps in the Korean War.
[2] He attended Arsenal Tech High School in Indianapolis, and was in the U.S. Marine Corps for three years (1953-1956) during the Korean War, becoming a sergeant.
[2][3] Thom's best known book is his third published novel, Follow the River (1981), about the 18th-century escape and journey of Mary Ingles, who had been captured by the Shawnee.
[3] For example, he ate bugs, worms, bark and roots to understand how Mary Ingles in Follow the River survived.
He purchased the cabin from a widower and dismantled and rebuilt it at a new location using early 19th century hand tools.
[8] He was previously married to Cody Sweet (an international platform lecturer), May 16, 1975; and Mari Silveus (a writer), May 28, 1984.
In 2013, Thom was made an honorary board member of the Kurt Vonnegut Memorial Library in Indianapolis.