In this article, I aim to show the substantial ways in which Edgar Zilsel can be considered to have been a politically engaged philosopher of science and provide a reconstruction of his philosophical work in the time before his forced emigration to the United States. In line with Monika Wulz and with my own reconstruction of the Vienna Circle’s political engagement, I reject Oliver Schlaudt’s 2018 thesis according to which Zilsel cannot be considered a politically engaged philosopher of science. My (...) reconstruction of Zilsel’s political engagement as a philosopher of science is based on his German-language writings (1916–32). I reconstruct Zilsel’s early philosophy of science insofar as it is relevant to his political commitment and show how Zilsel drew on his epistemological concept of “rationalization” to engage in public debate. I deal with Zilsel’s Marxism and his work as a teacher and scholar in the context of “Red Vienna.” In light of this evidence, I conclude that any conception of “politically engaged philosopher of science” that implies Zilsel was not entails an unreasonable conclusion and must, therefore, be reconsidered. (shrink)