Prestwood was raised in El Paso, Texas, where he became fascinated with the music he heard coming over the radio. While he was interested in music and had learned to play guitar, Prestwood instead studied education at the University of El Paso, and was teaching sixth grade when some friends invited him to join a cover band. It wasn't long before the group thought it would be a good idea to have a few originals in their repertoire, and Prestwood began writing songs for the first time at the age of 25. Five years later, Prestwood was hooked on songwriting, and when a friend from El Paso who was working in the Broadway theater said she could introduce him to people in the music business, he headed east and settled in New York.

After two years of scuffling and trying to catch a break as a singer/songwriter, producer Alan Lorber heard Prestwood's song "Dorothy" and thought it had potential. Lorber passed the tune along to noted Nashville producer Jim Ed Brown, and he in turn persuaded Jackie DeShannon to record it. A year later, the same song was heard by Judy Collins, and she not only decided to record it, she was eager to hear what else Prestwood had composed. Two of Prestwood's songs appeared on Collins' 1979 album Hard Times for Lovers, "Dorothy" and the title track, and the success of the album opened the door for his career as a tunesmith. Prestwood would go on to write major hits for Randy Travis ("Hard Rock Bottom of Your Heart"), Trisha Yearwood ("The Song Remembers When"), Crystal Gayle ("The Sound of Goodbye"), and Collin Raye ("On the Verge"). Other artists who have cut his songs include Anne Murray, Don Williams, Alison Krauss, Conway Twitty, Kathy Mattea, Jimmy Buffett, and many more. In 1991, BMI named Prestwood's "Hard Rock Bottom of Your Heart" Song of the Year, and in 2006, he was inducted into the Nashville Songwriters Hall of Fame. (Other 2006 inductees included Jimmy Buffett and Jim Weatherly.)

In 1993, Prestwood returned to his career as a performer when he appeared on the album Signatures III, in which several noted country songwriters performed their own works. Prestwood would appear on other sampler albums devoted to Nashville songwriters showcasing their wares (though by this time he was comfortably settled in Long Island), and recorded several self-released albums, including Ghost in This House, All the Way On, and The Fate of Fireflies. In 2016, Prestwood's longtime friend and collaborator Judy Collins released his solo album I Used to Be the Real Me through her Wildflower Records label; Collins contributed guest vocals on two tracks. When not busy with recording or penning songs for others, Prestwood teaches classes and workshops in songwriting, and has been a longtime member of the faculty of Manhattan's The New School. ~ Mark Deming