With the success of Carmina Burana, Orff disowned all of his previous works except for Catulli Carmina and the Entrata (an orchestration of "The Bells" by william Byrd (1539–1623)), which were rewritten until acceptable by Orff. Later on, however, many of these earlier works were released (some even with Orff's approval). As an historical aside, Carmina Burana is probably the most famous piece of music composed and premiered in Nazi Germany. Carmina Burana was in fact so popular that Orff received a commission in Frankfurt to compose incidental music for A Midsummer Night's Dream, which was supposed to replace the banned music by Mendelssohn. After several performances of this music, he claimed not to be satisfied with it, and reworked it into the final version that was first performed in 1964.

Carl Orff was born in Munich on 10 July 1895. His family was Bavarian and was active in the Army of the German Empire. His paternal grandfather was a Jew who converted to Catholicism.

In 1911/12, Orff wrote Zarathustra, Op. 14, an unfinished large work for baritone voice, three male choruses and orchestra, based on a passage from Friedrich Nietzsche's philosophical novel Also sprach Zarathustra. The following year, he composed an opera, Gisei, das Opfer (Gisei, the Sacrifice). Influenced by the French Impressionist Composer Claude Debussy, he began to use colorful, unusual combinations of instruments in his orchestration.

Moser's Musik-Lexikon states that Orff studied at the Munich Academy of Music until 1914. He then served in the German Army during World War I, when he was severely injured and nearly killed when a trench caved in. Afterwards, he held various positions at opera houses in Mannheim and Darmstadt, later returning to Munich to pursue his music studies.

Orff was a Roman Catholic. He was married four times: to Alice Solscher (m. 1920, div. 1925), Gertrud Willert (m. 1939, div. 1953), Luise Rinser (m. 1954, div. 1959) and Liselotte Schmitz (m. 1960). His only child Godela (1921–2013) was from his first marriage. She has described her relationship with her Father as having been difficult at times. "He had his life and that was that," she tells Tony Palmer in the documentary O Fortuna.

In 1924 Dorothee Günther (de) and Orff founded the Günther School for gymnastics, music, and dance in Munich. Orff was there as the head of a department from 1925 until the end of his life, and he worked with musical beginners. There he developed his theories of music education, having constant contact with children. In 1930, Orff published a manual titled Schulwerk, in which he shares his method of conducting. Before writing Carmina Burana, he also edited 17th-century operas. However, these various activities brought him very little money.

Orff is best known for Carmina Burana (1936), a "scenic cantata". It is the first part of a trilogy that also includes Catulli Carmina and Trionfo di Afrodite. Carmina Burana reflected his interest in medieval German poetry. The trilogy as a whole is called Trionfi, or "Triumphs". The Composer described it as the celebration of the triumph of the human spirit through sexual and holistic balance. The work was based on thirteenth-century poetry found in a manuscript dubbed the Codex latinus monacensis found in the Benedictine monastery of Benediktbeuern in 1803 and written by the Goliards; this collection is also known as Carmina Burana. While "modern" in some of his compositional techniques, Orff was able to capture the spirit of the medieval period in this trilogy, with infectious rhythms and simple harmonies. The medieval poems, written in Latin and an early form of German, are often racy, but without descending into smut. "Fortuna Imperatrix Mundi", commonly known as "O Fortuna", from Carmina Burana, is often used to denote primal forces, for Example in the Oliver Stone movie The Doors. The work's association with fascism also led Pier Paolo Pasolini to use the movement "Veris leta facies" to accompany the concluding scenes of torture and murder in his final film Salò, or the 120 Days of Sodom.

Orff's relationship with German fascism and the Nazi Party has been a matter of considerable debate and analysis. His Carmina Burana was hugely popular in Nazi Germany after its premiere in Frankfurt in 1937. Given Orff's previous lack of commercial success, the monetary factor of Carmina Burana's acclaim was significant to him. But the composition, with its unfamiliar rhythms, was also denounced with racist taunts. He was one of the few German composers under the Nazi regime who responded to the official call to write new incidental music for A Midsummer Night's Dream after the music of Felix Mendelssohn had been banned. Defenders of Orff note that he had already composed music for this play as early as 1917 and 1927, long before this was a favor for the Nazi regime.

Orff was reluctant to term any of his works simply operas in the traditional sense. For Example, he referred to his works Der Mond (The Moon, 1939) and Die Kluge (The Wise Woman, 1943) as Märchenopern ("fairytale operas"). Both compositions feature the same "timeless" sound, called timeless because they do not employ any of the musical techniques of the period in which they were composed, with the intent that they be difficult to define as belonging to a particular era. Their melodies, rhythms, and accompanying text form a unique union of words and music.

Orff was a friend of Kurt Huber, one of the founders of the resistance movement Weiße Rose (the White Rose), who was condemned to death by the [Volksgerichtshof] error: {{lang}}: text has italic markup (help) and executed by the Nazis in 1943. Orff by happenstance called at Huber's house on the day after his arrest. Huber's distraught wife, Clara, begged Orff to use his influence to help her husband, but he declined her request. If his friendship with Huber was ever discovered, he told her, he would be "ruined". On 19 January 1946 Orff wrote a letter to the deceased Huber. Later that month, he met with Clara Huber, who asked him to contribute to a memorial volume for her husband. Orff's letter was published in that collection the following year. In it, Orff implored him for forgiveness.

In pedagogical circles he is probably best remembered for his Schulwerk ("School Work"). Originally a set of pieces composed and published for the Güntherschule (which had students ranging from 12 to 22), this title was also used for his books based on radio broadcasts in Bavaria in 1949. These pieces are collectively called Musik für Kinder (Music for Children), and also use the term Schulwerk, and were written in collaboration with his former pupil, Composer and educator Gunild Keetman, who actually wrote most of the settings and arrangements in the "Musik für Kinder" ("Music for Children") volumes.

Gassenhauer, which Orff composed with Gunild Keetman, was used as the theme music for Terrence Malick's film Badlands (1973). Hans Zimmer later reworked this music for his True Romance (1993) score.

Orff died of cancer in Munich in 1982 at the age of 86. He had lived through four epochs: the German Empire, the Weimar Republic, Nazi Germany and the post World War II West German Bundesrepublik. Orff was buried in the Baroque church of the beer-brewing Benedictine priory of Andechs, south of Munich. His tombstone bears his name, his dates of birth and death, and the Latin inscription Summus Finis (the Ultimate End), which is taken from the end of De temporum fine comoedia.

However, in Orff's denazification file, discovered by Viennese Historian Oliver Rathkolb in 1999, no remark on the White Rose is recorded; and in Composers of the Nazi Era: Eight Portraits (2000) Kater recanted his earlier accusations to some extent.

Most of Orff's later works – Antigonae (1949), Oedipus der Tyrann (Oedipus the Tyrant, 1958), Prometheus (1968), and De temporum fine comoedia (Play on the End of Times, 1971) – were based on texts or topics from antiquity. They extend the language of Carmina Burana in interesting ways, but they are expensive to stage and (on Orff's own admission) are not operas in the conventional sense. Live performances of them have been few, even in Germany.