Remembered best as a bassist for the world-famous 1960s band The Four Seasons, Massi also served as a vocal arranger and singer for the popular group.
In the late 1950s, he joined The Four Lovers, a music group that rose to fame after changing its name to The Four Seasons.
When he ended his association with the Four Seasons in 1965, his position in the band was filled by Charles Calello and, later, Joe Long.
Born Nicholas Macioci, he grew up in Newark, New Jersey. He died of cancer in his early seventies.
He served as a musical mentor to Four Seasons frontman Frankie Valli.