13 (1st Westphalian) throughout the First World War on the Western Front in both combat and staff positions, earning the Iron Cross 1st and 2nd Class.

He formed and led the Westphalian “Freikorps von Pfeffer” in the Baltic states, the Ruhr and Upper Silesia until March 1920.

He began to be involved in right wing politics, joining the Völkisch-Social Bloc in 1924 and becoming the Chairman of its Landesverband (State Association) in the Province of Westphalia from May 1924 to March 1925.

[3] Pfeffer joined the Nazi Party in March 1925 (membership number 16,101) shortly after the ban on it in the aftermath of the Beer Hall Putsch was lifted.

In September 1925, he became a member of the National Socialist Working Association, a short-lived group of northern and western German Gauleiters, organized and led by Gregor Strasser, which unsuccessfully sought to amend the Party program.

[5] However, disputes and jealousies between them led to a reorganization ordered by Adolf Hitler on 20 June 1926 with Kaufmann remaining as the sole Gauleiter.

He was the first SA commander upon its re-establishment in 1925, following its temporary abolition in 1923 in the wake of the abortive Beer Hall Putsch.

Pfeffer saw the SA as a military/revolutionary institution that would eventually displace the Reichswehr to become a mass people’s army and overthrow the Weimar Republic.

Hitler accepted Pfeffer's resignation and on 2 September assumed personal command of the SA as Oberster SA-Führer.

Following the failed assassination attempt on Hitler in the 20 July 1944 plot, he was arrested once more and this time held for several months.

[14] His brother, Friedrich Pfeffer von Salomon (1892–1961), was an SA-Obergruppenführer, who served as the Police President in Kassel (1933–1936) and the Nazi Party Regierungspräsident in Wiesbaden (1936–1939; 1941–1943)[15]