Hennessy is a distinctive girls' name in United States, ranking #2937 in 2004 with 54 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 315.4%. In 2004, approximately 1 in every 34,002 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.