As a given name, it has traditionally been more masculine than feminine. In America however, after the variant Sydney became popular for girls, Sidney was used more for girls than boys between 1993 and 2019.
Very rare as an American given name before 1980, it increased in popularity in the 1980s and 90s. It got a boost in 2004 after the debut of the television series Lost, which featured a character by this name.
A famous bearer of the surname was James Madison (1751-1836), one of the authors of the American constitution who later served as president (and after whom Madison Avenue was named).
This name has been used in England since the 13th century, though it became more common in Scotland where it was borne by several kings. In the 17th century the Scottish king James VI inherited the English throne, becoming the first ruler of all Britain, and the name grew much more popular. In American name statistics (recorded since 1880) this name has never been out of the top 20, making it arguably the era's most consistently popular name. It was the top ranked name for boys in the United States from 1940 to 1952.
Famous bearers include the English explorer James Cook (1728-1779), the Scottish inventor James Watt (1736-1819), and the Irish novelist and poet James Joyce (1882-1941). This name has also been borne by six American presidents. A notable fictional bearer is the British spy James Bond, created by author Ian Fleming in 1953.