He was also an Archduke of Austria, Prince Royal of Hungary and Bohemia. Although Rainer suffered from a mild form of epilepsy, this did not visibly interfere with his military career. Rainer served as Viceroy of the Kingdom of Lombardy–Venetia from 1818 to 1848.
Rainer politics were increasingly unpopular, the Italians resented him for their lack of political freedom and for collecting revenues with so little benefit to them.
Throughout the 1840s, the political situation worsened to such an extent that in 1847, Metternich resurrected his 1817 plans for an Italian chancellery by sending his right-hand man count Charles-Louis de Ficquelmont to Milan as acting Chancellor of Lombardy–Venetia to restore the Austrian rule while taking over Northern Italy"s administration. But only a few months later, Ficquelmont was recall to Vienna to assume the leadership of the Council of war as the Revolutions of 1848 started.
Archduke Rainer"s mistakes as well as the lack of understanding between Rainer and Feldmarschall Graf Radetzky, were blamed for the disasters of the Italian Revolution of 1848. Titles and styles 30 September 1783 – 11 August 1783 His Royal Highness Archduke Ranier Joseph of Austria 11 August 1804 – 16 January 1853 His Imperial & Royal Highness Archduke Ranier Joseph of Austria.