The formation of a teacher's identity is considered a dynamic process influenced by internal and external contextual factors. This article explores the impact that external contextual factors have on teacher candidates' identities by presenting the findings of an empirical qualitative study that investigated the relationship between teacher candidates' beliefs and their demonstrations and representations of teaching and learning on a nationally standardised portfolio assessment. Metaphor analysis and stimulated recall were used to explore this relationship. The study found that teacher candidates' teaching demonstrations while student teaching and representations of teaching found in a nationally standardised portfolio assessment were severely constrained by cooperating teachers and scripted curriculums. However, the study also found that candidates could articulate the differences between their beliefs about teaching and learning and their demonstrations and representations of teaching and learning. Candidates routinely made suggestions in the portfolio assessment to align their future teaching more closely to their metaphors for teaching. The study concluded that candidates did not change their beliefs but took up temporary teaching identities based on these findings. They found ways to navigate the assessment and their (teaching) context while remaining committed to their teaching identity and beliefs about good teaching. This article suggests how education system contexts impact the formation of teacher candidates' identities and what teacher education programmes need to do to strengthen candidates' identities in the face of negative external influences.