Early life
Katzer was born on 31 January 1919 in Cologne, the sixth child of the carpenter Karl Katzer and Rosa Katzer (née Franke). Karl had been a secretary of the Kolping Society since 1902 and later administrative director from 1927 to 1938. He was also a member of the council of Cologne for the Centre Party from 1919 to 1933. In 1929, he joined the Jugendbund Neudeutschland, a Catholic organization affiliated with the Centre Party. Due to his father's social status, he attended a Realgymnasium, dreaming of becoming an architect, but the seizure of power of the Nazi Party made his father lose his mandates and positions. He was forced to leave the Realgymnasium in 1935 due to this. He then did a commercial apprenticeship at a Cologne textile company, where he worked as part of the Reich Labour Service from 1938 to 1940, and attended the Higher Technical School for the Textile Industry in Mönchengladbach from 1939 to 1942.
His service in the Nazi German Army started in 1939. During the Battle of Moscow, on December 7, 1941, he received a serious injury in the form of a gunshot wound to the lung. He afterwards became a Leutnant, becoming an instructor in Metz during the German occupation of France. He was briefly a prisoner of war by the U.S. Army in May 1945, but was soon after released.
In 1945, upon recommendation of Johannes Albers, he was placed in the Cologne Federal Employment Agency. Katzer would later say Albers "introduced him to politics", who was also his political mentor in addition to Jakob Kaiser. That year he also joined the CDU in Cologne upon its founding. In 1952, the local elections for North Rhine-Westphalia happened and the CDU won 31 of the 66 seats of the council of Cologne, and he was elected a member alongside people like Ernst Schwering. During this time period he also became the co-editor of the magazines "Soziale Ordnung" and "Betriebsräte-Briefes".
