His compositions would later include characteristics of polytonality (Second Symphony, 1944), atonality (Medea, 1946; Prayers of Kierkegaard, 1954), Twelve-tone technique (Nocturne, 1959 and the Piano Sonata, 1949), and even jazz (Excursions, 1944; A Hand of Bridge, 1959). Barber's composition were never lauded to be pathbreaking, but his compositions were an eclectic blend of the “musical currents hovering about in his time”. John Corigliano succinctly described Barber's style as "an interesting dichotomy of harmonic procedures — an alternation between post-Straussian chromaticism and often diatonic typical American simplicity."
With a background deeply rooted in vocals, Barber's love of poetry and his intimate knowledge and appreciation of the human voice inspired his vocal writing. Barber's most famous vocal compositions, Knoxville: Summer of 1915 (to words by James Agee) and Dover Beach (to words from a Victorian text by Matthew Arnold), were greatly successful and received critical acclaim, making a powerful case for Barber as one of the twentieth century's most accomplished composers for the voice.