Between 1953 and 1961 he served as director of the Franz Mehring Institute for training teachers in Marxist-Leninist Sociological Studies, which was a core (and for much of the time compulsory) base module for students at the Karl Marx University (as it was known between 1953 and 1991) of Leipzig.
[1][2] Lothar Gerhard Mosler was born in Ziegenhals (known, after 1944/45, as Głuchołazy), which was a small mining town on the southern frontier region of Upper Silesia.
Between 1934 and 1939 he was a member of the government-backed Deutsche Arbeitsfront ("German Labour Front") which had been created by the new government to replace the now outlawed trades unions.
He then, in 1945/46 took over the headship of a primary school at Cunewalde which, following frontier changes mandated by the allied leaders, was now on the extreme south-eastern edge of Germany's Soviet occupation zone.
It was an indication that he had been marked out for future advancement than between January and March 1947 he attended the regional SED party academy in nearby Ottendorf.
[1][2] In 1949 Mosler was appointed to a lectureship at the "Walter Ulbricht" Law Academy ("Deutsche Akademie für Staats- und Rechtswissenschaft...") in Forst Zinna.
[1][2] Following receipt of his doctorate Mosler accepted a professorship, still at the Karl Marx University of Leipzig, with the focus of his teaching still on the History of the Labour Movement.
In 1961 he resigned from his role as director of the university's Franz Mehring Institute, and in the same year became a member of the Senate Commission on Social Sciences.
In 1969 he undertook a five month leave of absence in order to undertake a piece of study at the University of Kiev on the History of the Soviet Communist Party.
On a national level, between 1971 and 1978 he belonged to the Commission for the Theology Section at the Ministry for Higher Education and Vocational Training ("Ministerium für das Hoch- und Fachschulwesen...").