Nancy Mills Barnett is a prominent American billionaire and a key member of the Mills family, which founded the medical supplies giant Medline Industries. She belongs to the fourth generation of the family, which has led the company for over 100 years.

Barnett grew up in the Chicago suburbs, part of the strategic family governance structure that oversaw the company’s massive expansion during the global pandemic. She became an official billionaire in December 2025 following the company's historic public listing.

• Core Company: Medline Industries (Medical supplies).
• Role: Major stakeholder and family director.
• Family Legacy: Sister of Medline Director Andy Mills and cousin to Chairman Charlie Mills.

Nancy Mills Barnett’s professional role has been defined by the long-term stewardship of the family business. Her structural contribution is tied to the board-level management of Medline, which was the largest privately held manufacturer of healthcare supplies in the U.S. until its public debut.

She was part of the leadership team that navigated the $30 billion leveraged buyout in 2021, where the family sold a 79% stake to a private equity consortium. Following the December 2025 IPO on the Nasdaq, the company’s market cap soared to over $55 billion, cementing her position among the world's wealthiest individuals.

• IPO Milestone: Medline's debut on Nasdaq in December 2025 with a record valuation.
• Governance: The company is now run by non-family executives, with Barnett and her cousins maintaining oversight via the board.