Antheil was baptized Georg Carl Johann Antheil and grew up in a family of Lutheran immigrants from Ludwigswinkel, Germany. He spent most of his time living in a more peaceful environment north of Trenton, New Jersey near Washington’s Crossing. Antheil was not Polish, as he claimed.  His father owned a local shoe store.  George's younger brother was Henry W. Antheil, Jr., diplomatic courier tragically killed over the Baltic Sea by the Soviets on June 14, 1940. Henry was recently recognized for his honorable service by the United States Department of State.
Antheil was "so crazy about music", said author Hugh Ford, that his mother sent him to the countryside where no pianos were available. George arranged for Barlow's Music Store in Trenton to deliver a piano to him.
Starting in 1916, Antheil studied piano under Constantine von Sternberg of Philadelphia and then Ernest Bloch of New York. Here, Antheil received formal instruction in composition. In 1922, Antheil was invited by agent Martin H. Hanson to replace the injured Leo Ornstein, playing Chopin on a European tour.
Reactions to his first performances were cool at best; His technique was loud, brazen, and percussive. Critics wrote that he hit the piano rather than played it, and indeed he often injured himself by doing so. Audiences in Budapest got so restless sometimes that Antheil would pull a pistol from his jacket and lay it on the piano to make people pay attention.