Hennessy is a distinctive girls' name in United States, ranking #3936 in 2025 with 37 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 184.6%. In 2025, approximately 1 in every 43,440 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.