Born Leonid Tisminetski, he joined the Romanian Communist Party (PCR) in the early 1930s. He engaged in illegal communist activities in Bucuresti, Galati, Bräila and Soroca. Later, he fought as a volunteer in the International Brigades during the Spanish Civil War, losing his right arm at the age of 24. In 1939, Tisminetski left for the Soviet Union, where he became a student of the Moscow State Linguistic University. After the start of Operation Barbarossa, in which Romania took part, he worked with Ana Pauker, Leonte Räutu, and Vasile Luca for the Romanian language branch of Radio Moscow, first as a newsreader, then as a writer. In 1948, Tisminetski and his family were sent to Soviet-occupied Romania, where he changed his name in 1949 to Leonte Tismaneanu, at the request of the PCR. He was named deputy director of Editura P M , later Editura Politica, the publishing house of the Communist Party and also held the Chair of Marxism-Leninism at the University of Bucuresti. In 1956, Tismaneanu, alongside Dean lorgu lordan and the academics Mihai Novico, Alexandru Graur, Ion Coteanu, and Radu Florian, took part in a University inquiry into the anti-communist statements of Paul Goma, a University student who later became a noted dissident and writer; led by lordan and supervised by the Securitate, the investigation culminated in Goma's expulsion from the Faculty and subsequent arrest.