John Edward Dearth II was born in 1950 in Framingham, Massachusetts, growing up in nearby Holliston. His father had survived the Pacific theater of World War II and was "obsessed" with jazz. D'earth, who added the apostrophe to his name later in life, says of his progenitor, "He was a maniac for music and for jazz music. He was my first teacher. He revealed to me mysteries of art and music that are priceless."
