Jennrich had married in 1938, and in July 1945, with a wife and four growing children to support, he launched himself as an independent trader in fruit and vegetables. In 1949 he was forced to abandon the project, however, because it was unprofitable.<ref name=FallEJlautMO/>
With the fall of Hitler in May 1945, party political involvement was no longer expressly outlawed in Germany. Almost immediately Jennrich re-joined the [[Social Democratic Party of Germany |SPD]], though there is no indication that he ever became a party activist. In a contentious development which was, as matters turned out, confined to the [[Soviet occupation zone]], in April 1946 the SPD [[Merger of the KPD and SPD|was merged]] with (or, it sometimes appeared, into) the [[Communist Party of Germany]]. The resulting [[Socialist Unity Party of Germany |"Socialist Unity Party" (''"Sozialistische Einheitspartei Deutschlands"'' / SED)]] was held out by the leadership and their Moscow backers as a vital bulwark against a return to NaziismNazism. Many believed that in [[Machtergreifung |1933]] it had been bitter divisions on the political left that had opened the way for [[Hitler cabinet |the Hitler government]] to take power. Within the part of Germany [[Soviet Military Administration in Germany|under Soviet military administration]] most members of the former [[Communist Party of Germany |Communist Party]] and many members of the [[Social Democratic Party of Germany |SPD]] lost no time in signing their party membership over to the new [[Socialist Unity Party of Germany |SED]]. The authorities went out of their way to make this very easy. Within the SED there is no indication that Jennrich ever became a party activist, and more than he had within the [[Social Democratic Party of Germany |SPD]] between 1945 and 1946. Nevertheless, in 1947 he brought himself to the attention of the authorities by resigning his party membership all together. Some time later, called upon to explain this - arguably "courageous" - move, he explained it as his reaction to having been told, when attending a meeting with party officials, that he had acquired his fruit and vegetables business only through the [good offices of] [[Socialist Unity Party of Germany |the party]]".<ref name=FallEJlautMO/>{{efn |"....weil mir in der Funktionärssitzung gesagt wurde, ich hätte mein Geschäft nur durch die Partei bekommen".<ref name=FallEJlautMO/>}}
After losing his business in 1949 Jennrich undertook a succession of short term jobs until 1 June 1953, when he accepted a position as a gardener with a Magdeburg-based [[Landwirtschaftliche Produktionsgenossenschaft |Landwirtschaftliche Produktionsgenossenschaft (LPG / ''"agricultural/horticultural cooperative"'']].<ref name=FallEJlautMO/> Meanwhile, in October 1949 the [[Soviet occupation zone]] had been relaunched and rebranded as the [[Group of Soviet Forces in Germany |Soviet sponsored]] [[German Democratic Republic |German Democratic Republic (East Germany)]] and, following western rejection in May 1952 of [[Stalin Note |Stalin's proposal for German reunification on Stalin's terms]], subjected to an intensified programme of wide-ranging and far-reaching "[[sovietization]]".<ref name=Sowjetisierung>{{cite web |title=Sowjetisierung in Wirtschaft und Landwirtschaft |author=Stephan Merl |url=https://d-nb.info/1031444181/34 |work=Europäische Geschichte Online (EGO) |publisher=Institut für Europäische Geschichte (IEG), Mainz |date=15 June 2011 |accessdate=8 April 2022}}</ref>
