Tan founded the fast food chain Jollibee in 1978, after having started it as an ice cream parlor in 1975. Through expansion and acquisitions of Greenwich Pizza Corp. which enabled it to enter the pizza-pasta segment. In early 2006, Jollibee Foods Corp. bought out the remaining shares of its partners in Greenwich Pizza Corporation, equivalent to a 20% stake, for P384 million in cash. As of August 2008, Tan's Jollibee has a total of 1,480 stores worldwide including Jollibee, Red Ribbon, Chowking, Greenwich, Manong Pepe's, Mang Inasal and Tita Frita's Uling Uling.
As of November 2015, Forbes estimated his net worth at US$2.6 billion.