#3041

Donald MacMillan

United States 56 years old

Overview

Source of Wealth
Cargill
Residence
Wayzata, Minnesota

Biography

Donald MacMillan is one of 21 billionaire heirs to Cargill, America's largest private company.

His great-grandfather, W.W. Cargill, founded the business as a single grain warehouse on the end of an Iowa railroad line in 1865.

He's one of nine billionaire siblings who inherited stakes in the company from their father John H. MacMillan III, who died in 2008.

The family still owns roughly 90% of Cargill, which did $154 billion in 2025 sales across food, agriculture, financial and industrial divisions.