 Tumbelaka's father, Johan Frederik Tumbelaka, was a medical doctor who worked for the Dutch East-Indies.Johan and his wife (whose last name was Sinyal) were both from the Minahasa region in North Sulawesi.Tumbelaka married Neltje Zus Ticoalu and the couple had two children, Fajar Yahya Tumbelaka and Taufik Tumbelaka.