Joel was elected as a city councilor in Oldenburg, serving from November 1930 to March 1933. He next was elected to the
Landtag of the
Free State of Oldenburg on 17 May 1931, remaining a member until May 1933 and serving as its president from 16 June 1932. After the
Nazi seizure of power, Joel served as special
Staatskommissar (state commissioner) for the Free State of Oldenburg from March to 6 May 1933. After
Carl Röver was appointed
Reichsstatthalter (Reich governor) of the state, Joel succeeded him as
Minister-president of the Oldenburg state government on 6 May 1933. He remained at the head of the administration until the end of the Nazi regime in May 1945. He concurrently served as the minister for foreign affairs, interior affairs, trade and transport. In August 1932, Joel was appointed as the Deputy
Gauleiter of
Gau Weser-Ems. He served successively under
Gauleiters Carl Röver and
Paul Wegener until 5 May 1945, becoming one of the longest-serving Deputy
Gauleiter. On 29 March 1936, he was elected as a deputy to the German
Reichstag from electoral constituency 14 (
Weser-Ems) serving until the fall of the Nazi regime. From 1937 to 30 January 1939, and again from November 1943 to May 1945, he also served as leader of the Gau personnel office (
Gaupersonalamtsleiter). From 1 September 1939 to 16 November 1942, Joel was Reich Defense Advisor in Gau Weser-Ems and a member of the Defense Committee of
Wehrkreis (Military District) XI. A member of the
Sturmabteilung (SA), he attained the rank of SA-
Brigadeführer on 9 November 1937 and was assigned to the leadership corps of SA-
Gruppe Nordsee. In the closing days of the
Second World War,
Gauleiter Paul Wegener was made Supreme
Reich Defense Commissioner-North and left for
Flensburg. Consequently, Joel ran the affairs of Gau Weser-Ems as acting
Gauleiter in Wegener's absence from 26 April 1945. British forces already were overrunning the Gau, and all German forces in northwestern Germany laid down their arms on 5 May 1945 in accordance with the terms of the
German surrender at Lüneburg Heath. Joel was arrested on 27 May and
interned in
Esterwegen. == Postwar life ==