Like his father, Prince Xavier de Bourbon-Parma was educated at the Jesuit seminary at Feldkirch, and later studied agriculture in France as well as political and economic sciences. He seems to have
had an early preference for France and, in 1914 at the beginning of World War I, wanted to join the French army. However, a French law forbade foreign princes to be enlisted and, as a result, both Xavier and Sixte joined the Belgian army and both became captains in the Artillery.
Also together with his brother Sixte, in 1917 Xavier had a role in secret peace negotiations on behalf of their brother-in-law, the Austrian Emperor Karl I, between Austria and France. Sadly these failed and, in 1918, the French Prime-Minister Cl‚menceau, hoping to divide his enemies, published the proposals. The Austrians and the Germans were furious, even though Emperor Wilhelm II had been briefed in advance by the Austrian Emperor. However, it became worse when
Czernin, the Austrian Prime-Minister, also denied knowledge, even though he had been aware in advance as well as of the contents. This affair was shattering for the Austrian Emperor and contributed to the demise of the Austrian Empire.
After the end of World War I, Xavier obtained French nationality and visited Turkey and Central Africa. In 1927 he married Madeleine de Bourbon-Busset, a member of a very rich French family, and they became the parents of two sons and four daughters.
On 23 January 1936, Don Alfonso Carlos, last of the Carlist pretenders to the Spanish throne, issued a declaration in which he appointed Xavier as Regent of the Carlist cause, as he was unable to appoint his successor. After the death of Don Alfonso Carlos, the Comuni¢n Tradicionalista appointed Xavier as the successor of Don Alfonso Carlos, which made him a pretender to the Spanish throne. In the person of Xavier the Carlist party had a vocal point as well as a reason to exist.
However, Spain had been a republic since 1931 and in 1936 was at the beginning of the Spanish Civil War which would last until 1939. In 1937 Xavier visited Spain to be with his wounded brother Ga‰tan and, during this journey on 6 December at Salamanca had a meeting with Franco.

At the outbreak of World War II, Xavier again joined the Belgian army but only until Belgium was taken by the Germans. In the following years he had an important role with the French resistance until he was imprisoned in a concentration camp in Dachau where, he also found his brother Louis. Here he refused "elite" treatment he could have received as a member of a royal family.

He had aged considerably when he returned from Dachau in 1945. The years after the war he lived in Paris or in either of the two chateaus inherited from his wife's family. Most of his time was dedicated to their estates but also in keeping up his rights to the Spanish throne. However, the latter was done so quietly that, outside Spain, hardly anyone knew that there was a Carlist party. This changed in 1964 when his eldest son, Charles Hugues, became engaged and married Princess
Irene of The Netherlands.
In 1974 his Austrian nephew, Robert, Duke of Parma, died. As this made Xavier, aged eighty-five, head of the family, he became styled Duke of Parma. His last years were marred by the dissent between his two sons and he died, on 7 May 1977, at Zizers in Switzerland.
 

Source: Leo van de Pas