Hennessy is a distinctive girls' name in United States, ranking #4007 in 1999 with 29 recorded births. The name reached its all-time peak in 2019 with 82 births ranking #2239. Since 1996, the popularity has increased by 123.1%. In 1999, approximately 1 in every 61,165 girls born was named Hennessy. STABLE Recent data shows the name is currently stable.