MacMillan was born in Orono, Minnesota, the great-grandson of company founder W.W. Cargill. He was a graduate of Blake School and Yale University.
MacMillan spent 44 years at Cargill, including nearly 20 years as chairman and Chief Executive Officer from 1976 until his retirement in 1995.
Heir to Minnesota company that piles food on America's plates. William Cargill, son of Scottish sea captain, started Cargill as a grain storage house in Iowa after Civil War. Will's son-in-law John MacMillan took reins 1909. Whitney: last family member to serve as chief executive, stepped down 1995. Family owns 88% of company, employees the rest. Today sales exceed $120 billion. Net profits in 2008: nearly $4 billion, up 69% from previous year as global demand for commodities soared. Company controls food from stable to table; manufactures animal feed, meat, crops. Also involved in commodities trading, risk management. Owns majority of publicly traded fertilizer firm Mosaic.
With a net worth of $5.1 billion, Whitney MacMillan was listed on the Forbes 400 as the 128th richest American in 2019. With his wife, Betty, MacMillan also supported numerous charitable and educational programs in the Twin Cities and around the country, with a focus on values-based education, health care, the environment and culture.
MacMillan served on numerous boards including the International Peace Institute, the EastWest Institute, the Salzburg Global Seminar and the University of Minnesota's Humphrey School of Public Affairs.