As a given name, it was used on the American sitcom Murphy Brown (1988-1998) for both the mother and son of the main character. By 1998 it was more popular as a name for girls in the United States, perhaps further inspired by a character from the movie Jerry Maguire (1996).
Due to its favourable meaning, this name was popular among early Christians, being borne by many early saints and four popes. It has been used in England since the Middle Ages, though it has been more popular in continental Europe. A notable bearer was the German composer Felix Mendelssohn (1809-1847).
Though it has never been popular in the English-speaking world among Christians, it has historically been a common name for Jews, who have used it as an Americanized form of names such as Isaac, Israel and Isaiah.
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.
As an English name it was not used until after the Protestant Reformation. It was utilized by George Eliot for the title character in her novel Silas Marner (1861).