Career
In 1928, after attending Middle School, Kubel became an industrial clerk. Kubel was arrested in 1937 and was convicted to a one-year prison term for preparation of high treason. He was drafted into the Volkssturm, a branch of the military, in 1944, and deserted soon thereafter.
In May 1946, after having joined the Social Democratic Party of Germany, Kubel was appointed prime minister of Braunschweig by the British occupation forces.
He held this position until the state was merged into Lower Saxony in November 1946. From 1951 to 1955 and from 1957 to 1970, he had various cabinet-level positions in the government of Lower Saxony.
As minister, he also served on the Volkswagen Group"s advisory board from 1965 to 1970. Kubel was Minister President of Lower Saxony from 1970 to 1976.
As such, he served as President of the Bundesrat in 1974/75.