 After serving two years as an intelligence agent in the United States Army, McMillan worked in investment banking, was CFO of Ruddick Corp. from 1970 to 1976 and was CEO of Harris Teeter Super Markets from 1977 to 1983.He served on the Mecklenburg County board of commissioners and chaired its board of social services before being elected to Congress in 1984.He did not run for re-election in 1994.