After the mobilization in July 1914, he was called up to service in the Austro-Hungarian army on August 3, 1914. In October his unit was sent to the Russian front; on December 21, 1914, he was captured by the Russians. At the POW camp in Pokrov, he was involved in the prisoners’ self-government, and in July 1916 he voluntarily joined the Serbian army, in which he was named a platoon commander. In December of that year he became a member of the officers’ staff under General J. Cervinka and on June 12, 1917, he was appointed to command the 8th Rifle Regiment. After a brief period of study at the school of trench warfare in Jassách, he was promoted to the rank of captain and appointed battalion commander on August 29, 1918. Returning to Czechoslovakia as a major in the summer of 1920, he became deputy commander of the 8th Infantry Regiment, and on November 17, 1922, was named its commander. Between 1924 and 1928 he took courses for senior commanders, and in early 1929 was appointed commander of the 16th Infantry Brigade in Místek; in the summer of that year he was promoted to the rank of general. In 1930 he became deputy commander of the Provincial Military Command in Košice, and later served, in turn, as commander of the brigade in Znojmo, as deputy commander of the division in Brno, and as commander of the II. group. He was in the last-named post at the time of the mobilization in September 1938.
Anti-German resistance
After the March 1939 occupation, several generals and senior officers of the Czech army established an illegal military resistance group called Defense of the Nation. Slunečko became the regional military commander of Moravia-West, based in Brno, and headed the Alex intelligence group under the code name of General Slunecek. The command of ON was almost totally destroyed between 1939 and 1941 as the Gestapo gradually arrested and executed many of its members. The group's remaining leaders regrouped in Bohemia and Moravia under Zdeněk Novák; after further arrests, Slunečko became the leader of ON and relocated to Prague, where he appointed General Kutlvašr as commander of the capital. After the start of the Prague Uprising, Alex placed itself under the leadership of the Czech National Council.
Prague Uprising
On May 5, 1945, General Slunečko ordered the Prague military headquarters, "Bartos," and all units outside Prague to revolt against the Nazi occupiers. At 11 A.M., under his direction, the Czech police occupied the radio, telephone exchange, railway station, main post office, and other strategic locations in the city. The Prague Uprising fully broke out at about noon. On May 8, Slunečko headed a delegation of the Czech National Council to which the German occupiers surrendered in Český Brod. After Karel Kutlvašr's liberation from the prison in Pankrác, he took command of all units at Alex's headquarters and Slunečko became his deputy.
After the war
After VE Day, Alex was closed down and on May 25 František Slunečko, now a brigadier general, was appointed provisional commander of the first army corps in Prague. On October 28 he was named commander and promoted to the rank of divisional general. He retired on June 1, 1946. Like many former officers and resistance fighters, he later faced various provocations, charges, and investigations. Although he was not convicted of anything, after being released from custody of the State Court, he was demoted to the rank of private in 1950 and was forced to move from Prague to Branžež.
