William Fleming Mackey (January 3, 1858 – July 10, 1912) was an American lawyer and politician from New York.
He was admitted to the bar in 1879, and initially continued working in the law office as managing clerk.
In the 1888 United States House of Representatives election, he was the Democratic candidate for New York's 32nd congressional district,[3] but he lost to John M. Farquhar.
Shortly after arriving in Buffalo, he helped form the Cleveland Democracy and served as its president in 1887, 1888, and 1892.
[2] In 1898, Mackey was elected to the New York State Senate as a Democrat, representing the 47th District.