John Mars, heir to the Mars, Inc. confectionery and pet-care empire, is one of America’s wealthiest and most private billionaires, stewarding a family business that spans iconic brands like M&M’s, Snickers, Pedigree, and Royal Canin. Alongside his siblings, he helped expand Mars beyond candy into food and animal health, reinforcing the company’s reputation for secrecy, long-term ownership, and decentralized management. Despite the scale of Mars’ global operations—among the world’s largest privately held companies—John Mars has remained almost entirely out of the public eye, shaping the business through discretion, values-driven governance, and deeply held family traditions.