Rooney is an Irish surname, from the Gaelic Ó Ruanaidh, "descendant of Ruanaidh", a personal name usually translated as "champion". As a girls' first name it owes most of its recent visibility to the actress Rooney Mara, who uses her middle name, a family surname. In the United States Rooney was too rare to be recorded in 2000; it climbed from number 4133 in 2015 to number 1963 in 2024 and ranked number 2235 among girls in 2025.