At both national and international levels, no other subject on the school curriculum is afforded more time and attention than literacy. This has led to claims that literacy is a ‘curriculum bully’(Cervetti et al., 2006). The current study examines how the concept of disciplinary literacy (Shanahan & Shanahan, 2008) can be used to integrate literacy with subject-area learning in a harmonious manner. Adopting a mixed methods design, the study comprises three phases. Phase 1 (QUAL) draws on in-depth interviews with primary and post-primary teachers (n=30) to investigate how literacy is conceptualised in various disciplines across upper primary and post-primary school. Drawing on design-based research methods, Phase 2A (QUAL→←quan) captures the experiences of primary teachers (n=6) and students (n=131) engaging with disciplinary literacy in science, history and visual arts for the first time. Phase 2B (QUAN) broadens the findings of Phase 1, utilising quantitative measures to compare and contrast the literacy perceptions and practices of primary and post-primary teachers (n=455). Synthesis of findings from across phases revealed that both primary and post-primary teachers generally placed a high value on the teaching of literacy. Though teachers were positively disposed to integrating literacy with other subjects, predominantly narrow and traditional conceptualisations of literacy underpinned this integration. Disciplinary literacy was not well represented in typical accounts of practice. Discontinuities were evident between primary and post-primary school literacy practices and between in- and out-of-school literacies. Classroom-based work with primary teachers highlighted the significant depth of knowledge and changes in practice required to link literacy with disciplinary learning in multiple subjects. Tailored professional development and carefully curated instructional materials (e.g. text sets) were crucial to the enactment of higher-order literacy practices in science, history and visual arts. The benefits of disciplinary literacy for primary students were manifold. Associated pedagogical approaches demonstrated significant potential to support student engagement, deepen the critical reading of texts and scaffold varied ways of thinking and communicating. Crucially, the findings illustrate that the pursuit of literacy skills need not come at the expense of a broad and balanced curriculum.