Hennessy is a distinctive girls' name in United States, ranking #4700 in 1998 with 23 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 76.9%. In 1998, approximately 1 in every 76,821 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.