He was born Francis Stephen Castelluccio on May 3, 1934, in Newark, New Jersey. Valli began his music career in the early 1950s, forming a group called The Variatones. In 1960, he joined The Four Seasons, and the group quickly became one of the most popular acts of the decade. With Valli as lead singer, the Four Seasons released a string of hit singles, including "Sherry," "Big Girls Don't Cry," "Walk Like a Man," and "December, 1963 (Oh, What a Night)."
The group's popularity declined in the late 1960s, but Valli continued to perform and record as a solo artist. He has released several albums and singles, and has also appeared in a number of films and television shows. In recent years, Valli has toured with a new version of The Four Seasons.