The sixth and youngest child of businessman and philanthropist
Charles Custis Harrison and his wife Ellen Nixon Waln Harrison, Eustis grew up in a prominent
Philadelphia family whose social circle included some of the most influential people of their day. Her father, Charles C. Harrison, was the grandson of John Harrison, who established the first chemical factory in the United States. Charles owned a highly profitable sugar refinery, which he and his partners sold for a reported price of $10 million. He then became the provost at his alma mater, the
University of Pennsylvania, and raised an estimated $11 million for the university over 16 years. Eustis’s mother was the great-granddaughter of
Robert Morris, who helped fund the American Revolution and the great-great-granddaughter of
John Nixon, who was chosen to do the public reading of The Declaration of Independence in Philadelphia four days after it was signed. Ellen Harrison was also active at the University of Pennsylvania, raising money for the university hospital and overseeing the landscaping of the university grounds. ==Personal life==