This paper reports on research into the challenges of implementing a critical writing pedagogy within a teacher education program in Australia. Participants in this study are student teachers enrolled in a compulsory subject that requires them to develop a knowledge of the role of language and literacy across the secondary school curriculum and to show personal proficiency in literacy (according to government specifications of graduate outcomes for teacher education programs). To gain an understanding of how language has shaped their lives, students write a narrative about their early literacy experiences - a task which they find very challenging, especially in comparison with the formal writing of other university subjects. Rather than reminiscing about their childhood, they are encouraged to juxtapose voices from the past and present, and to combine a range of texts within their writing. They thereby create a heteroglossic text (Bahktin) that stretches their repertoires as language users and enables them to develop a socially critical awareness of language and literacy, including the literacy practices in which they engage as university students. The narratives raise questions about the extent to which tertiary students are able to formulate a critical language awareness that will subsequently inform their professional practice as secondary teachers.