Caroline Werner was born in Rochester, New York, on January 22, 1894, the daughter of Lillie Boller Werner and New York State Court of Appeals Judge William E. Werner. She attended public schools in Rochester until the 8th grade, completing her education in various private schools. She also spent a year at "Pension Glucker," a girls school in Munich, and traveled throughout Europe during her teens. On March 25, 1920, Miss Werner married Frank E. Gannett, who had moved to Rochester two years earlier when he and two business associates purchased the ROCHESTER TIMES-UNION. A strong supporter of her husband's business and political careers, Mrs. Gannett campaigned actively for her husband when he sought the Republican nomination for the presidency in 1940. She also served as a board member of the Gannett Company, as Vice President and Director of the Gannett Foundation, and was involved in the Frank E. Gannett Nespaperboy Scholarships and the Gannett Youth Center.
Remaining active in politics after Frank Gannett's death in 1957, she served as co-chairwoman of the Senior Americans for Nixon-Lodge Committee in 1960.
Caroline Gannett's social and civic works were numerous. She served as a member of the Board of the Convalescent Hospital for Crippled Children, member of the War Council of New York (working in centers caring for children of war plant workers during World War II), vice-chairwoman of the First Aid Department of the Rochester Chapter of the American Red Cross (1941-1944), member of the Honorary Board of Partrons of Hartwick College (1944), honorary chairwoman of the Lights-on-for-the-Blind Drive of the Rochester Eye Bank (1958), and as a member of many other organizations. In 1947 she was appointed to the New York State Board of Regents, a position she held until 1963. Mrs. Gannett was also affiliated with the Syracuse University Youth Development Center (1958-1961) and the 1960 White House Conference on Children and Youth. She died on January 4, 1979.