Hennessy is a distinctive girls' name in United States, ranking #3035 in 2020 with 53 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 307.7%. In 2020, approximately 1 in every 30,481 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.