Forbes Magazine assessed him to be a billionaire by the 1970's [1] He was born on July 5, 1930,[2] the son of John H. MacMillan, Jr. and Marion Dickson.
After graduating from the Berkshire School, he received his bachelors degree from Brown University in Providence, Rhode Island in 1953.
He maintained his relationship with the university as a member of the board of trustees and with philanthropic gifts to fund scholarships and build the W. Duncan MacMillan Hall.
[4] They had four daughters, Sarah MacMillan of California, Katherine Tanner of Florida, and Lucy Stitzer and Alexandra Daitch, both of Connecticut, all of whom survived him.
[5] MacMillan died on October 31, 2006[4] of an apparent heart attack at his winter home near Jupiter, Florida, aged 76.