Brennan is a distinctive boys' name in United States, ranking #1003 in 2025 with 226 recorded births. The name reached its all-time peak in 2009 with 1,464 births ranking #242. Since 1996, the popularity has decreased by 74.7%. In 2025, approximately 1 in every 7,558 boys born was named Brennan. STABLE Recent data shows the name is currently stable.