Hennessy is a distinctive girls' name in United States, ranking #2643 in 2008 with 70 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 438.5%. In 2008, approximately 1 in every 27,010 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.