Joseph P. Gaffney was a prominent lawyer and public official in Philadelphia, Pennsylvania, serving as City Solicitor during the administration of Mayor W. Freeland Kendrick (1922-1928). He was the paternal grandfather of Frank Gaffney Jr. In 1926, as City Solicitor, Gaffney successfully defended the city's decision to open the sesquicentennial celebration on a Sunday against a lawsuit from the Methodist Men’s Committee, arguing it did not violate blue laws, while maintaining that Sunday baseball games constituted a breach of peace. As a known Catholic in early 20th-century Philadelphia—a hotbed of anti-Catholic bigotry—Gaffney faced fierce opposition from nativist Protestant groups and the Ku Klux Klan, with critics accusing him of being at the center of a Catholic network infiltrating city institutions and claiming that the Protestant mayor was under his control. Gaffney continued in public service, acting as counsel for the Board of City Trusts into the 1950s, including in cases related to Girard College and other estates.