Treliving began his career as a constable with the Royal Canadian Mounted Police. In 1968, while still with the RCMP, Treliving noticed the growing popularity of Boston Pizza and purchased the rights to open a restaurant in Penticton, British Columbia. While in Penticton, he met George Melville, a chartered accountant. Melville acted as Treliving's business consultant for four years until 1973, at which time he became Treliving's partner in the business. In 1983, Treliving and Melville acquired the Boston Pizza chain from then-owner Ron Coyle. The two then divested 15 of their restaurants to other franchisees and converted one restaurant to a corporate training restaurant. By 1995, the chain had grown to 95 restaurants in Western Canada with sales in excess of $110 million (CA$). Currently Boston Pizza and Boston's the Gourmet Pizza (US and Mexico division) have over 435 restaurants throughout North America.
