Brandes was born in Dresden, the son of an estate owner at Gut Althof near Insterburg (today, Chernyakhovsk) in East Prussia.

He fulfilled his military service as a one-year volunteer in the Royal Prussian Army with the 7th (1st Rhenish) Hussars Regiment "King Wilhelm I" headquartered in Bonn, and served as an officer in the reserves.

After passing the Referendar state examination, he worked as an apprentice lawyer in Gumbinnen and Königsberg and at the Regierungsbezirke (governmental districts) of Trier, Saarbrücken and Hildesheim.

[1] From 1894, Brandes managed his father's estate, became known as an excellent livestock breeder and became active in political affairs as a leader of East Prussian conservatives.

[3] When the Weimar Republic was formed in 1919, Brandes was elected to the East Prussian Landtag as a German National People's Party deputy, serving until its abolition in October 1933.