He saw active service in Algeria, and became chef d'escadron in 1849 and lieutenant-colonel in 1850. He took part as a colonel in the Crimean War, and after the battle of Inkerman received the rank of general of brigade.
In 1863 he was promoted general of division. When the Franco-German War broke out in 1870, de Cissey was given a divisional command in the Army of the Rhine, and he was included in the surrender of Bazaine's army at Metz. He was released from captivity only at the end of the war, and on his returr was at once appointed by the Versailles government to a command in the army engaged in the suppression of the Commune, a task in the execution of which he displayed great rigour.
From July 1871 de Cissey sat as a deputy, and he had already become minister of war. He occupied this post several times during the critical period of the reorganization of the French army, and served briefly as Prime Minister of France from 1874 to 1875. In 1880, whilst holding the command of the XI corps at Nantes, he was accused of having relations with a certain Baroness Kaula, who was said to be a spy in the pay of Germany, and he was in consequence relieved from duty. An inquiry subsequently held resulted in de Cissey's favour (1881).