Joan Kroc was born on August 27, 1928, in West St. Paul, Minnesota. Her father, Charles Smart Mansfield, was a store keeper, later a railroad telegraph operator and salesman. Her mother, Gladys Bonnebelle Mansfield was born April 5, 1906 in Luck, Wisconsin to Herman Conrad Peterson and his wife Emma Bonnebelle. Joan’s mother was an accomplished violinist. She studied music at the MacPhail School of Music in Minneapolis and started teaching at age 15. In 1945, she married Rawland F. Smith, a Navy veteran, who, eventually, became a McDonalds franchisee. The couple’s only child, a daughter named Linda, was born the following year. Joan Kroc met McDonald’s Corp. founder Ray Kroc while playing organ at the Criterion Restaurant St. Paul, Minnesota in 1957. Kroc said in his autobiography that he “was stunned by her blond beauty”. They carried on a secret relationship until they both divorced their spouses and married in 1969. Following Kroc’s death in 1984, she inherited his fortune. Joan’s first philanthropic endeavor was Operation Cork in 1976 in La Jolla. It aimed to inform doctors and other health workers about the dangers of alcoholism. Ray and Joan Kroc owned the San Diego Padres professional baseball club. After Ray’s passing in 1984, she tried to donate the team to the city of San Diego (the San Diego Padres went on to win its first ever National League pennant that year), but Major League Baseball rules forbid public team ownership. Kroc sold the team in 1990 and turned her attention to philanthropy. She drew controversy when she alluded to paying star and future Hall of Fame shortstop Ozzie Smith to maintain her garden at a time when he was refused a raise by her team’s general manager.

The Joan B. Kroc Foundation donated $18.5 million to the San Diego Hospice Corporation (now known as San Diego Hospice and The Institute for Palliative Medicine) in 1985 to create its multi-purpose hospice center. The donation covered the cost of planning, land acquisition (6.5 acres (26,000 m2)), construction and interior furnishings of the center. In 2002, Kroc Center, a large Salvation Army community center that she helped fund—to the tune of $87 million—opened to the public. She later bequeathed an additional $1.6 billion to open Salvation Army Kroc Centers across the nation, the largest one-time gift ever recorded. Several institutions in the San Diego area are named after her, including the think tank Joan B. Kroc Institute for Peace and Justice at the University of San Diego, the St. Vincent de Paul Joan Kroc Center for the Homeless in downtown and the Kroc-Copley Animal Shelter in the Morena District. America’s leading ‘Peace’ institution is probably the University of Notre Dame’s Joan B. Kroc Institute for International Peace Studies, established and endowed by Joan herself. Joan Kroc preferred to give donations anonymously, but recipient organizations often insisted on publicizing her gifts, hoping to attract new donors. She also supported the Ronald McDonald Children’s Charities and Ronald McDonald Houses. As the Padres owner, she started Major League Baseball’s first employee-assistance program for players and staff with drug problems.

Joan Kroc was also politically active. In 1985, she spent millions of dollars in support of nuclear disarmament, which included reprinting the book Missile Envy by Helen Caldicott, as well as publishing ads in major newspapers calling for disarmament. In response, Cal Thomas, a conservative syndicated columnist, called her a “McNut.” She is affectionately known by the citizens of Grand Forks, North Dakota and East Grand Forks, Minnesota as the “Angel” because of her anonymous $15 million donation to assist the cities after a devastating flood occurred there in 1997. She was revealed as the source of the funds after reporters tracked down ownership of the jet that she used to fly into the area to survey the damage. Upon her death in 2003, a bequest of $225 million was made to National Public Radio (NPR) including $5 million to her local public radio station, San Diego’s KPBS. Joan died of brain cancer on October 12, 2003 at Rancho Santa Fe, California, at the age of 75. She was buried at the El Camino Memorial Park in Sorrento Valley, San Diego.