Orff is most known for Carmina Burana (1938), a "scenic cantata". It is the first of a trilogy that also included Catulli Carmina and Triunfo de Aphrodite, which reflected his interest in medieval German poetry. While "modern" in some of his compositional techniques, Orff in the trilogy is able to capture the spirit of the medieval period with infectious rhythms and easy tonalities. The medieval poems written in an early form of German and in Latin were often racy, but without descending into smut for smut's sake.
In pedagogical circles he is probably best remembered for his Schulwerk (1930-35), translated into English as his "Music for Children." Its simple musical instrumentation allowed even untutored child musicians to perform the piece with relative ease. Much of his life Orff worked with children, using music as an educational tool. Both melody and rhythm are often determined by the words, in either the German or English production. There is a feeling of enthusiasm that echo the joy the performers obviously feel in creating such beautiful music.
Orff was reluctant to call any of his works just operas. For example, he called Der Mond ("The Moon") (1939) a "Märchenoper": Fairytale Opera. Die Kluge ("The Wise Woman") (1943) would fall into the same category. In both there is that same medieval or timeless sound without actually copying the musical idioms of the period. The melodies, rhythms and, with them, the text are so memorable that they can be recalled years after one hearing, which is proof of a rare and flawless union of words and music.
Of his Antigone (1949) Orff said specifically, that it was not an opera, but a Vertonung, a "musical setting" of the ancient tragedy. The text is an excellent German translation, executed by Friedrich Hölderlin, of Sophocles' play of that name. The orchestration, particularly for the percussion section, is greater than tremendous. Some have called the style minimalist, which it may be in terms of melodic line, but it matches the emotional content of the original play with ease.
His last work, De Temporum Fine Comoedia ("A Play of the End of Time") had its premiere at the Salzburg music festival on August 20, 1973, by Herbert von Karajan and the Cologne Radio Symphony Orchestra and Chorus. In this highly personal work Orff presented a mystery play in which he summarized his view of the end time, sung in Greek, German, and Latin.