He was most notable for his service in the Romanian Campaign of World War I. Paul was born in Lindau as the son of the district administrator Johann Baptist Kneussl and his wife Klara, née Vigl.

[2] After graduating from a trade school he went to a two-year technical college and entered the Bavarian Army in 1880 as a One-year volunteer in the 4th Field Artillery Regiment.

As a premier lieutenant (since June 13, 1892) he became regimental adjutant in 1889 and studied at the war academy from 1892 to 1895; which attested him qualifications for the general staff, the higher adjutantage and the academic teaching of tactics.

After his promotion to major general on January 23, 1913, Kneußl received the Knight's Cross of the Order of Merit of the Bavarian Crown from the hands of his king.

Shortly before the end of the war, in August, he was appointed commanding general of the XV Royal Bavarian Reserve Corps, which he returned to the homeland after the Armistice of 11 November 1918.