Bonfanti's music career began in 1965 when he saw The Beatles on Ed Sullivan. That experience eventually led him to join the band The Mods. This band was later renamed The Choir, and their recording of "It’s Cold Outside" reached the national charts in 1967.
In 1970, Jim, Wally Bryson, Dave Smalley and Eric Carmen formed Raspberries who made four albums, eight singles, many road trips (including Carnegie Hall), national and international success, including a gold record for their major hit "Go All The Way".
Following two albums both released in 1972, creative tension came to a head sparked largely by Carmen's creative dominance over the contributions of fellow members. After the release of the Raspberries' third album, Side 3, Smalley and Bonfanti departed Raspberries to form their own band, Dynamite.