Poppe earned her upper secondary school qualification in Oranienburg in 1971. She was still in school when she first began to develop a critical view of the GDR system. Initially this had to do with experiences that revealed the differences between the officially propagate youth culture and her own ideas. The music, the clothing, the hair styles and the behaviour of many young people did not fit into the official picture of GDR youth in these years, leading to clashes between students, Poppe among them, and the authorities. It was also in school that she first saw how the state reacted to independent political views. In 1967, she and two other school students wrote a letter to the Volkskammer, the GDR legislature, in which they asked questions relating to the reunification of Germany, among other things. The letter got no written response but it did trigger considerable discussion about the political attitude of the three students. In the end, the two girls were allowed to remain at school: their parents were SED members and it was assumed that this indicated that they might yet be brought to the socialist cause. The boy was expelled, despite being the best student in the class: his parents were not in the SED, and he was active in the Young Congregation. This experience helped to shape Poppe’s political views, as did the *Prague Spring and the anti-authoritarian student movement in the West.

Moving to Berlin in 1971 to study at Humboldt-Universität (she planned to become a teacher of art and history) brought Ulrike Poppe into contact with other young people who were unwilling to submit to the rules imposed from on high. In Berlin, she came to recognise how the regime and its representatives pruned, skewed or falsified historical facts and contexts to bolster its legitimacy. She read banned books, discussed them in various circles and encountered social and cultural realities that were never reflected in the official media or textbooks.

In 1973, she interrupted her studies, partly because it had become clear to her that she could not serve the system as a teacher but also because she wanted to study psychology. Her attempt to switch subjects was vetoed by the FDJ. She subsequently worked in a “transit home” for children and youth and, from 1974, as a nurse’s aide in a locked ward of the Charité hospital in Berlin. Both of these jobs confronted her with aspects of socialism as it existed in reality that were either never spoken about or flat-out denied by society. For Poppe, the way the state treated the children she met in the children’s home, children who had been psychologically harmed by adverse social factors or were the victims of domestic abuse, was not merely depressing: a system capable of treating society's most vulnerable members with such inhumanity had to be sick at its very core. She still associated communism with the idea of liberation, but she felt certain that the SED leadership had betrayed socialism. These experiences also prompted her to distance herself from the basic ideological patterns she had been taught.

She met Gerd Poppe in the mid-1970s and married him in 1978. Through him, she came into contact with other opposition figures as well, including Robert Havemann. She began to work at Berlin's Museum for German History in 1976. There, she and some of her colleagues organised cultural events that soon began to draw hundreds of attendees. The leading Party officials at the museum saw these activities as “hostile to the state” and banned them. This marked the beginning of a series of major clashes between Poppe and her employer over various issues. 

At around this same time, Poppe came into contact with groups, active largely in the underground, that were discussing new models for society and with other groups which met to discuss specific topics such as child-raising, education, housing policy and political participation in the GDR. These latter struck her as both more appealing and more productive: they were less dominated by men, less isolated and had less of a tendency towards intellectual arrogance. In the late 1970s, these groups started opening themselves more and more to the outside world and became part of the independent peace movement, which was taking shape at the time.

Together with her husband, Gerd Poppe, she organised readings by critical and sometimes also persecuted literary figures in their flat from 1980–1983. In this, the Poppes were continuing a tradition started by the poet Frank-Wolf Matthies, who arranged readings of this kind in Berlin before he emigrated to the West. The Poppes also joined other parents to organise an alternative nursery school in their home district of Prenzlauer Berg (their children were born in 1979 and 1981). This made it possible for both parents continue working while their children were cared for it an atmosphere free of state influence. The alternative nursery existed from early 1981 until 14 December 1983, when it was destroyed and banned at the order the state.