Hattie Louise Harris was born on September 28, 1903 in Warwick, Rhode Island. She was the daughter of Samuel P. Harris and Faustine Borden Harris. Miss Harris graduated from Pembroke College at Brown University in 1926, where she majored in economics. From 1928 to 1946 she worked as the secretary in her father’s printing business, Samuel P. Harris Incorporated. She studied organ with T. Tertius Noble, the English-born organist and composer, and from 1928 to 1945 she gave recitals, taught piano and organ, and served as the organist in various churches.
Miss Harris is best known for her historical research concerning the history and authorship of the Pledge of Allegiance to the flag and for her writing regarding C.A. Stephens, a medical doctor who wrote for the magazine The Youth’s Companion from 1871 until his death in 1931. She published several books regarding the American flag and the history and authorship of the Pledge of Allegiance, including The Flag over the Schoolhouse (1971), Old Glory: Long May She Wave (1981) and Time for Truth (1987). The latter two titles are sequels to the first.
Miss Harris was a great admirer of C.A. Stephens, having read The Youth’s Companion as a child. She established and was the curator of the C.A. Stephens Collection at Brown University, where she wrote several books about him, including A Comprehensive Bibliography of C.A. Stephens (1965), None but the Best (1966), A Chuckle and a Laugh: A Tale of the C.A. Stephens Collection (1967), The Star of the Youth’s Companion (1969), and Our Great American Story-teller (1978). In addition, she compiled and edited several volumes of Stephens' stories, including Molly's Baby: A Little Heroine of the Seas (1969), Under the Sea in the Salvador (1969), C.A. Stephens Looks at Norway: Story-teller's Edition (1970), Charles Adams Tales (1973), and Little Big Heart (1974).
Miss Harris was also interested in genealogical research. She was an elected member of the Clan MacLaren Society of Edinburgh, Scotland, and was a member of several honor societies, including the International Biographical Association and the American Biographical Institute Research Association. She was listed in a number of biographical directories, including Notable Americans of the Bicentennial Era and the International Register of Profiles. Her memberships included the American Historical Association, the National Historical Society, the American Heritage Society, the National Trust for Historic Preservation, the American Guild of Organists, the Audubon Society and the National Wildlife Society. She was a member of the Central Baptist Church in Providence.
Miss Harris’ contribution of a percentage of her estate in the name of her grandfather, Frederick P. Borden, was instrumental in helping to create what is now the Warren Alpert Medical School at Brown University. When the School's first class graduated in 1975, Miss Harris was recognized as a founder of the Medical Education Program at Brown. She was also a benefactor of Rhode Island Hospital, where she was an active volunteer worker with children.
Miss Harris passed away in Providence, Rhode Island, on July 19, 1993.