T . Denny Sanford is a self-made American banking and credit card billionaire who has become one of the most prolific philanthropists in the United States. He bought a small, state-chartered bank in Sioux Falls, South Dakota, and built it into First Premier Bank, which became the foundation of his fortune. He found a highly profitable, though controversial, niche by specializing in providing high-interest-rate credit cards to subprime, or high-risk, borrowers through the bank's subsidiary, Premier Bankcard.

This business made him a multi-billionaire, and he has since dedicated his life to giving away his entire fortune. A signatory of the Giving Pledge, his philanthropic contributions now total well over a billion dollars. His giving is primarily focused on health care and medical research, with his largest and most transformative gifts being made to the Sioux Valley Hospitals and Health System in South Dakota, which was renamed Sanford Health in his honor. He has also made massive donations to pediatric health initiatives and scientific research facilities across the country.