Franz Freiherr von John was born in Bruck an der Leitha as the fourth child of an Austrian officer.[1] He was schooled at the military academy in Wiener Neustadt and joined the Archduke Franz Karl Infantry Regiment Nr. 52 in 1835 as a lieutenant.[1] In 1845 he served as a lieutenant on the General Quartermaster staff.[1] In 1848 he served under Radetzky as a captain during the First Italian War of Independence where he distinguished himself at Goito.[1]
In 1857 he was promoted to colonel, ennobled as a Baron, and became a regimental commander.[1] In 1859 he was chief of staff of the VI Army Corps in South Tyrol.[1] In 1861 he was promoted to major general and became the head of the General Staff of the Italian army commanded by Benedek.[1]
When the Austro-Prussian War started, John remained chief of staff of the South Army in Italy under the command of Archduke Albrecht.[2] During the campaign he distinguished himself at the Battle of Custoza (24 June 1866) and was promoted Feldmarschall-Leutnant on the battlefield.[2] After the defeat of Benedek's North Army at Königgrätz, he accompanied the Archduke to the northern theatre of war.[2]
In September 1866 he became Chief of Staff of the Austrian Army (September 1866 – March 1869) and in November 1866 he also became Minister of War (November 1866 – January 1868).[1] The same year he was appointed a lifelong member of the House of Lords.[1] As war minister, John served in the governments led by Count Belcredi, Count Beust and Prince Auersperg.[1] During his time as war minister he carried out an army reform based on general conscription.[1]
In December 1868 he became Inhaber of Infanterie Regiment Nr. 76.[1]
In March 1869 he resigned as chief of the general staff and became commanding general in Graz.[1] In 1873 John was promoted to Feldzeugmeister.[1] In 1874 he again became Chief of the General Staff of the army, a post he held until his death in Vienna on 25 May 1876.[1]
