Friedrich Christian was made a lieutenant in the 1st Royal Saxon Leib-Grenadier Regiment No. 100 at the age of 10, in accordance a family tradition of the House of Wettin. In 1913, he studied at the Military Academy in Dresden. During World War I, he served General Staff on the Western Front. He received several medals for bravery. He was very gifted linguistically and was sent on diplomatic missions to King Alfonso XIII of Spain, to Sultan Mehmed V of Turkey and to Emperor Charles I of Austria.