Born in Saarlouis, Rhenish Prussia, Knorr entered the Prussian Navy in 1856.

On 12 November 1870, during the Franco-Prussian War, Knorr commanded the gunboat Meteor in a battle with the French aviso Bouvet near Havana, for which he was awarded the Iron Cross 2nd Class.

Beginning in 1874, Knorr took part in a voyage through the Pacific Ocean to discuss trade negotiations with Tonga on behalf of the German Empire.

He then commanded a cruiser squadron travelling to Zanzibar and negotiated with its sultan for the acquisition of a strip of German colonial territory.

Raised to the German nobility on 18 January 1896, he received the Order of the Black Eagle on 15 June 1898.