Questions about who politicians speak for, and on what terms, sit at the heart of contemporary debates about political representation. First speeches are the institutionalised ‘rite of passage’ in which a newly elected representative introduces themselves to parliament. They offer a rare site where this question is answered explicitly. Yet there are few studies of first speeches as a genre, and fewer still that read them as sites of political claim-making. This paper draws on an interpretive analysis of a purposively sampled corpus of Australian federal first speeches from the 1970s to the present, from a data set of first speeches from the Reusable and Accessible Public Interest Document Community Data Lab. Drawing on an interpretive approach to political analysis, it reads first speeches as sites where representatives construct their political identities and constituencies, using a framework that distinguishes the formal, invoked and constituted dimensions of constituency claims as a way of exploring how politicians represent themselves and those they speak for. Pilot analysis suggests that the collectivities brought into earlier speeches are characteristically anchored in party tradition, class and occupational identity, while more recent speeches foreground biography, care and lived experience as the grounds of political claim-making. The paper reflects on what this shift reveals about the changing terms on which political authority is claimed in Australia.