Hennessy is a distinctive girls' name in United States, ranking #2239 in 2019 with 82 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 530.8%. In 2019, approximately 1 in every 20,458 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.