Sickingen is posthumously known as "the last knight" (der letzte Ritter), an epithet he shared with his contemporaries Chevalier de Bayard and Emperor Maximilian.

Having fought for the emperor Maximilian I against Venice in 1508, he inherited large estates on the Rhine, and increased his wealth and reputation by numerous private feuds, in which he usually posed as the friend of the oppressed.

[1] In the contest for the imperial throne upon the death of Maximilian in 1519, Sickingen accepted bribes from King Francis I of France, but when the election took place he led his troops to Frankfurt, where their presence assisted to secure the election of Charles V. For this service he was made imperial chamberlain and councillor, and in 1521 he led an expedition into France, which ravaged Picardy, but was beaten back from Mézières and forced to retreat.

[1] After the failure of the French expedition, Sickingen, aided by Hutten, formed, or revived, a large scheme to overthrow the spiritual princes and to elevate the order of knighthood, the Knights' War.

A large army was soon collected, many nobles from the upper Rhineland joined the standard, and at Landau, in August 1522, Sickingen was formally named commander.

The Archbishop of Trier, Palatine Elector Louis V, and the Landgrave of Hesse decided to move against him, and having obtained help from the Swabian League, marched on Nanstein Castle.

In 1889, the Hutten-Sickingen Monument of Bad Münster am Stein-Ebernburg in Rhineland-Palatinate, Germany, was built above the town to commemorate Hutten and Sickingen's role in the Knights' War.