Born in the Bronx, New York, he was raised in Bergenfield, New Jersey, where he attended Bergenfield High School. His mother worked for the publishing house Prentice Hall and his father in a paper factory. He showed an interest in music and studied piano with Sal Mosca.
Gaudio grew up in more comfortable middle class surroundings than the other members of the Four Seasons, which caused some tension and differences early on. He was a cerebral person, interested in reading and learning. He stayed out of trouble and kept a mild manner about him, which proved useful during negotiations throughout his career.
He rose to musical fame at the age of 15 as a member of The Royal Teens when he co-wrote the hit "Short Shorts". In 1958, while he and the group were promoting the single, they met Frankie Valli and his group the Four Lovers as they prepared to perform on a local television program. Wearying of touring, he left the Royal Teens soon afterward, and the rest of the group dissolved shortly afterwards.
One year after he ceased touring, Gaudio joined the Four Lovers. While commercial success was elusive, the group was kept busy with steady session work (with Bob Crewe as the producer) and a string of performances at night clubs and lounges.
First gained fame as a member of the rock group The Four Seasons. He was also a producer on many of their records and a prolific songwriter for not only the Seasons but many other artists as well.
Formerly a member of the 1950s rock group The Royal Teens and composer of their hit song, "Short Shorts".
Elected to the Rock and Roll Hall of Fame (as a member of The Four Seasons). 
Inducted into the Songwriters Hall of Fame. 
His favorite songs are "Tequila" by The Champs, "Angel" by Sarah McLachlan, "Your Love Keeps Lifting Me Higher & Higher" by Jackie Wilson, "Green Onions" by Booker T. & the M.G.s, "You've Lost That Loving Feeling" by The Righteous Brothers, "Earth Angel" by The Penguins, "My Boyfriend's Back" by The Angels, "What's Going On" by Marvin Gaye, "All I Have To Do Is Dream" by The Everly Brothers and "December '63 (Oh What A Night)" by Frankie Valli. (Source: BBC Radio 2 "Tracks of My Years").
Father of Lisa I. Gaudio of Paoli, PA; former father-in-law of Anthony V. D'Amico, Cleveland, OH; father-in-law of James A. Kazanjian of Paoli, PA; maternal grandfather of Brianna Danielle D'Amico Alcorn of Alexandria, VA, and her husband, Joshua Mark Alcorn of Washington, DC.
"Jersey Boys" at the Ahmanson Theatre in Los Angeles, CA, was awarded the 2007 Los Angeles Stage Alliance Ovation Award for Touring Production.
The Four Seasons were inducted into the 2017 New Jersey Hall of Fame in the Performing Arts category.