Greig's business, John Greig Real Estate, was established in 1970 and specializes in residential, commercial and industrial brokerage services. Other industry accolades and positions held by Greig in his career include president of the Real Estate Institute of NSW 1989 to 1991 and Life Fellow; president of the Real Estate Institute of Australia 1993 to 1995; board member & trustee of the REIA superannuation fund; past chairman of the Real Estate Services Council of NSW (Government Licensing Body & Regulatory Board); and past chairman of the NSW Property Industry Advisory Board. In 2000 he was awarded the Order of Australia medal for services to the real estate industry and the community.

In his first speech, Greig revealed his goal was to make FIABCI even more relevant to the day-to-day business of its member through increased use of the Internet and associated technologies. In a prepared statement, Greig says, "There is serious business to be done through the FIABCI international website."

Greig also notes that he is "intensely committed to the protection of private property rights as the basis of family security and economic freedom and under my leadership I hope to see FIABCI strengthening its partnership with the United Nations in this regard."