At age 17, while still a high school student, Heinecke took over from the Bangkok World's advertising manager. One year later, he founded Inter-Asian Enterprise, to supply office cleaning services, and Inter-Asian Publicity, a radio advertising company, using US$1,200 he had borrowed. He later sold Inter-Asia Publicity to Ogilvy & Mather. In 1967, he founded Minor Holdings, which would over the next four decades would grow into The Minor Group, including more than 30 companies..