Family
- father Edward Dennehy: deceased
- mother Hannah Dennehy: died at age 78 on November 4, 1991 of lung cancer
- brother Edward Dennehy Jr:
- brother Michael Dennehy:
- daughter Elizabeth Dennehy: born on October 1, 1960; appeared on the CBS daytime soap, "The Guiding Light"
- daughter Kathleen Dennehy:
- daughter Dierdre Dennehy: pursued a PhD in psychology
- son Cormac Dennehy: born c. 1993; adopted
- daughter Sarah Dennehy: born c. 1995; adopted; biological sister of Cormac Dennehy
