Hennessy is a distinctive girls' name in United States, ranking #3452 in 2017 with 45 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 246.2%. In 2017, approximately 1 in every 38,353 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.