When she was in her late teens, she and her family immigrated as refugees to the United States in 1940 to escape Nazi occupation[citation needed] after the German invasion during World War II.

[3] In the 1950s, Yale began a project in collaboration with the American Philosophical Society of Philadelphia, to publish the papers of Benjamin Franklin.

A review in The New England Quarterly, noting the difficulty of defining Franklin's character, described it as a "superb book [that] provides most of the essential ingredients for a judgment, including some new materials and scores of ingenious perceptions.

In addition to serving as associate editor of the Franklin Papers Project, Lopez was a senior research scholar in the Department of History.

[3] She appeared as a guest speaker on a variety of television talk shows,[3] including the PBS Think Tank, and its Was Benjamin Franklin the First American?, which aired 29 May 2003.

[6] In 2002, Lopez was the adviser to the PBS mini-series, Benjamin Franklin, directed by Ellen Hovde and Muffie Meyer.