In 1966, the Jefferson County Public Library (JCPL) created a 501(c)(3) corporation called the Jefferson County Public Library Trust & Endowment Association. This entity was created to provide a way for patrons, citizens, and supporters of the public library to make tax-deductible donations to JCPL. In 1984, the Jefferson County Library Foundation was filed as the trade name for the Trust & Endowment Association. Soon after, the JCPL Board of Trustees appointed the first JCLF board of directors.
The mission of JCLF's first board of directors was "to actively seek out any resources available to our library from personal, corporate, and private foundation philanthropy, in order to provide for programs and projects which are beyond the government's means to support, but which will enhance JCPL's growth and excellence as a public institution." JCLF continues to follow that mission today by providing funding support for library services and programs benefiting children, adults, families, and library staff.