He started working in the produce business at age 16, as a produce clerk at Sheridan Fruit Company, Inc., in Southeast Portland,[4] followed by Corno's Food Market.[1] For 11 years, he worked at Fred Meyer, eventually serving as produce district manager, and worked personally with eponymous grocer Fred G. Meyer, a major influence.[1]
At age 30, Zupan and his coworker Chuck Gaylord bought Zim's grocery store near Gresham, Oregon.[1] After selling his share of the business, Zupan went on to operate ThriftWay and Food Pavilion stores, before finally opening his first Zupan's Market on W Burnside in Portland.[1] He opened his fourth Zupan's Market store in Raleigh Hills in 1996.[4] At the time, Zupan's Markets was an Oregon corporation with administrative offices in Washington.[4] Zupan was well known for his unique skill in presenting fresh produce to consumers.[1]
Zupan handed his business over to his son Michael in 2000, although he remained involved in the business.[1] Even after his son took the helm, the stores were designed not to distract from fresh food.[5] At the time of his death in 2011, the store was known as an upscale gourmet grocery store chain.[1]