Rubinstein was born in Łódź, Congress Poland (part of the Russian Empire for the entire time Rubinstein resided there) on January 28, 1887, to a Jewish family. He was the youngest of seven children of Felicja Blima Fajga (née Heiman) and Izaak Rubinstein. His father owned a small textile factory.
Rubinstein's birth name was to be Leo, but his eight-year-old brother claimed that "His name must be Artur. Since Artur X (a neighbor's son) plays the violin so nicely, the baby may also become a great musician!" And so he was called Artur, although in English-speaking countries, he preferred to be known as Arthur Rubinstein. His United States impresario Sol Hurok, however, insisted he be billed as Artur, and records were released in the West under both versions of his name.