Karl Alfons Deisenroth was born in Bad Hersfeld on February 2, 1913. From 1919 to 1923, he attended Bad Hersfeld elementary school and then the local state grammar school, where he graduated in 1930.

From April 1930 to October 1932, Deisenroth was trained as an industrial clerk at the company Börner Bros. At the same time, in 1931 and 1932, he completed a training course at the Walther private commercial school in Bad Hersfeld. Deisenroth was taken on by the training company until he left in 1935 to start his military service. From 1937 until the start of the war, he was employed as a purchasing assistant and later as purchasing manager at Maschinenfabrik Wiesbaden and then at AEG Berlin. From 1939 to 1945, Karl Alfons Deisenroth was deployed in the war as an airplane pilot and squadron captain. Here he reached the rank of Captain of the Reserve.

After the end of the Second World War, Karl Alfons Deisenroth returned to his home town of Bad Hersfeld and, thanks to his good knowledge of English and French, took on the position of interpreter in the mayor's office. His duties ranged from day-to-day business to correspondence with the American military government. Deisenroth's main concern was to create living space for the civilian population of Bad Hersfeld by releasing occupied buildings. On November 1, 1946, the town council commissioned him with the reconstruction of the spa and put him in charge of it. Deisenroth also supervised the drilling of the Vitalbrunnen from 1947, which led to Hersfeld's further development into a spa.

In 1948, Karl Alfons Deisenroth moved to the Hessian Ministry of Economics and Transport. As spa consultant, he was responsible for the reconstruction of the Hessian spas until 1949. Deisenroth then took over the management of the Hessian state spas Bad Schwalbach, Schlangenbad and Bad Salzhausen. This was followed in 1956 by a position as commercial director of the Bad Ragaz spa and health resorts in Switzerland and from 1958 to 1965 as spa director and managing director of the Bad Mergentheim spa administration. Between 1961 and 1963, he took part in military exercises as a reserve officer alongside his work as spa director. Before Deisenroth moved to Wiesbaden in 1967, he was the spa director and managing director of the Bad Liebenzell spa administration from January 1, 1966.

In all of his appointments, Karl Alfons Deisenroth was largely responsible for the reconstruction and expansion of the spas, the reorganization of the administration and the economic restructuring of the companies.

On April 1, 1967, Karl Alfons Deisenroth was appointed spa director by decision of the magistrate of the state capital of Wiesbaden and thus became head of the spa operations. Karl Alfons Deisenroth also successfully campaigned for the reorganization of the spa industry in Wiesbaden. Thanks to clever structural innovations, he succeeded in doubling the number of spa beds. He also achieved year-round utilization of the spa facilities, which led to a significant increase in municipal revenue through the spa tax. Deisenroth was largely responsible for the development of the spa structure in the Aukammtal. Among other things, the establishment of the German Clinic for Diagnostics (DKD) can be attributed to his efforts. Together with various municipal offices, Deisenroth was able to convince Wiesbaden to become a spa location. He also initiated further structural development processes that made the city attractive as a spa and excursion destination. He was also involved in the establishment of the Aukammtal thermal baths.

Deisenroth was involved in voluntary work as chairman of the Association of Hessian Spas, he was a board member of the Economic Association of German Spas and Health Resorts, a board member of the Hessian State Tourism Association, a member of the Tourism Advisory Board of the Hessian Ministry of Economics and Technology, a member of the Business Management Committee of the German Spas Association and an expert consultant for tourism and commercial enterprises in Germany and abroad. Karl Alfons Deisenroth retired on February 29, 1972. He died on February 27, 2000 in Wiesbaden.