After the war Ley returned to university, gaining a doctorate in 1920. He was employed as a food chemist by a branch of the giant IG Farben company, based in Leverkusen in the Ruhr. Enraged by the French occupation of the Ruhr in 1924, Ley became an ultra-nationalist and joined the Nazi Party soon after reading Adolf Hitler's speech at his trial following the Beer Hall Putsch in Munich. Ley proved unswervingly loyal to Hitler, which led Hitler to ignore complaints about his arrogance, incompetence and drunkenness. Ley's impoverished upbringing and his experience as head of the largely working-class Rhineland party region meant that he was sympathetic to those elements in the party who were open to socialism, but he always sided with Hitler in inner party disputes. This helped him survive the hostility of other party officials such as the party treasurer, Franz Xaver Schwarz, who regarded him as an incompetent drunk.