He was of Hakka Chinese descent, born the fifth of 12 children to Gladstone Vernon and Maisie Chang in Kingston, Jamaica. His father was a second generation Chinese Jamaican born to Chinese immigrants while his mother was born in Guyana, also of Chinese descent. Upon the death of Maisie’s brother, Chang’s parents adopted five of their then-orphaned nieces and nephew. This newly blended and inter-related family now comprised 12 children and was raised together with Chang’s other cousins on two back-to-back streets on which were constructed five houses, each built for an individual “Chang” family. In total, 35 cousins lived side-by-side “around-the-block” of five houses. Gladstone and Maisie, along with Gladstone’s brothers and sisters, owned a successful bakery and several, other businesses on the island. From an early age, Gladstone and Maisie Chang insisted that all 12 children pursue a university education; after he was educated as St. George’s College, Jamaica.
Chang emigrated in 1967 first to Troy, New York and then to Toronto, Ontario, both times to attend university. He earned an engineering degree from the University of Toronto and went on to earn his qualifications as a Chartered Accountant and Chartered Financial Analyst and largely pursued a career in finance.
He worked for Coopers & Lybrand for a time, and until 1983, when he and some partners bought into a small Toronto mutual fund management company that managed $5 million in assets. This predecessor company would grow and develop into CI Financial, which in 2014 managed $100 billion of investments. Chang started at CI Financial as vice-president and chief operating officer, and was promoted to COO and president in 1996, becoming president and CEO in 1998, and then chairman and CEO from 1999 to 2010. At that time, the Company had become the second largest publicly traded mutual fund company in Canada. Chang also owned an investment holding company, G. Raymond Chang Ltd., and founded software firm Mercatus Technologies Inc. Chang was also a shareholder and board member of various other Canadian and Jamaican companies.