Carl Alexander was the third son of Albrecht, Duke of Württemberg and his wife, Archduchess Margarete Sophie of Austria. He also had four younger sisters. He was taught at home and attended high school after 1914. In World War I, he fought on the Western Front in Italy. He resigned as captain following the German Revolution of 1918–1919 from active military service and within a few months became a postulant at the Abbey of St. Martin in Beuron. He entered the novitiate in 1920 as "Brother Odo", taking vows in February 1921. His father succeeded King Wilhelm II, a distant cousin, as head of the House of Württemberg in October of that same year. Brother Odo was ordained a priest in 1926. In the summer of 1930, Father Odo was sent to the Abbey of St. Martin, in Weingarten, not far from Castle Altshausen. He held several offices in the monastery and was active with different Catholic youth organizations. Because of his position and his family's conservative Catholic values, he was involved in opposition to National Socialism as early as 1933 and was interrogated by the Gestapo several times. He left the abbey and traveled to Württemberg in 1934. The Nazis expelled Father Odo from Germany in 1936, and he took refuge in monasteries in Switzerland and Italy. In Switzerland, he founded International Catholic Refugees and traveled through Europe.
In 1940, after the Swiss government informed him that they could not 100% guarantee his safety, Father Odo decided to emigrate to the United States. Before leaving, he destroyed his personal papers, which consequently cannot be used to trace his activities in detail. From 1941 Father Odo lived in Washington, D. C., continuing his work with refugees and enabling Jews to emigrate from Germany and its conquered territories. From 1943 onward, he was involved in the pastoral care of Germans in an American prisoner of war camps. He convinced the Federal Bureau of Investigation that the Duchess of Windsor was sleeping with the German ambassador in London, Joachim von Ribbentrop. He remained in constant contact with him and continued to leak secrets. The historian and archivist of the House of Württemberg, Eberhard Fritz, believes that Claus von Stauffenberg's opposition to Adolf Hitler may have been partly motivated by his relationship with the House of Württemberg.. Stauffenberg was personally acquainted with Father Odo and was well aware of pockets of resistance against the Nazis. After the end of World War II, Father Odo founded the Central European Rehabilitation Association, with the aim of providing war-torn Central Europe with food, clothing, medicine, and other necessities. In 1949, after CERA had fulfilled its function and was dissolved, Father Odo returned to the abbey of St. Bartholomew in Germany. He left the monastery in 1952 because of a heart condition, returning to his family castle in Altshausen. There he spent the last years of his life and was a refounder of the Yellow Hussars of Altshausen. Father Odo was briefly interviewed and mentioned in the 1959 biography of his cousin Queen Mary of Teck by the British biographer James Pope-Hennessy. According to his wishes, Father Odo was buried in the cemetery of the Abbey of St. Martin at Weingarten, Württemberg.
