Prior to taking up painting and sculptor, Antonietta studied at both the British Museum and the Royal Academy of Music, London where she graduated in piano. She left London for Paris in 1919 where she stayed until 1924 when she left for Rome. It was from this point onwards, and following courses taken at the Academy of Fine Arts that she began to paint. After moving to Paris in 1930, she began to concentrate on sculpture.
Co-founded the Scuola Romana movement (a form of expressionism) with her husband, Mario Mafai. Remembered primarily for her naturalistic forms and her symbolic sculptures.