Nancy Sharon Maginnes was born in White Plains, New York, in 1932 to an affluent family. Her father, Albert Bristol Maginnes, was a successful corporate lawyer and college football athlete, while her mother was an interior designer. Nancy attended Mount Holyoke College, graduating with a degree in history in 1955. Her sharp analytical mind and interest in post-war geopolitics drew her straight into New York policy circles rather than conventional suburban domesticity.
During the late 1950s, she joined the staff of New York Governor Nelson Rockefeller. She served as a core foreign policy researcher and international affairs specialist on Rockefeller’s personal staff and later worked on his Commission on Critical Choices for Americans. It was in Rockefeller’s foreign policy advisory orbit in the mid-1960s that she first encountered Henry Kissinger, who was then a Harvard professor and consultant to the governor.
Their intellectual relationship preceded their romance by nearly a decade. Colleagues described her as intensely private, meticulous, and widely read in European strategic history. When Henry became President Richard Nixon's National Security Advisor in 1969, Nancy remained in New York, working on global security analysis and policy papers. By the time they wed, she was 41 years old, an established professional woman with an independent career and deep domain knowledge of international treaties.