Hennessy is a distinctive girls' name in United States, ranking #2422 in 2018 with 74 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 469.2%. In 2018, approximately 1 in every 22,979 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.