Jack Hennessy may refer to: John Francis Hennessy (1853–1924), Australian architect John Francis (Jack) Hennessy (1887–1955), his son, Australian architect John M. Hennessy, American financier and philanthropist Jack Hennessy (politician) (1951–2024), member of the Connecticut House of Representatives
See also Jackie Hennessy, Irish footballer John Hennessy (disambiguation)