Hennessy is a distinctive girls' name in United States, ranking #3761 in 2000 with 34 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 161.5%. In 2000, approximately 1 in every 53,411 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.