A substantial body of scholarly research has examined decision-making in domestic high courts, but international judicial behavior remains relatively poorly understood. Building on research that uses judges’ career background as a proxy for their motivations at the European Court of Human Rights, we deploy a new measure of judicial career backgrounds and a new dataset of the Court’s free expression decisions. We combine quantitative analysis of judicial votes with qualitative analysis of judges’ signed dissenting opinions to advance existing understandings of the Court’s decision-making. We show that former diplomats are less likely to support contested free expression claims than their colleagues with different career backgrounds. In their published opinions, former diplomats are more likely to voice concerns about the objectionable nature of particular speech acts and to call for broad judicial deference to state restrictions on such speech. By contrast, judges with prior service in domestic government roles, as well as judges with career backgrounds outside of government, exhibit greater tolerance of objectionable speech, greater willingness to impose European-wide standards, and more frequent invocation of extra-European legal standards. Our findings contribute to broader debates about the influence of individual-level preferences on judicial behavior in international courts.