The role of systemic functional grammar (SFG) is usually investigated in postgraduate courses and in‐service programmes with experienced teachers. In contrast, this study examines the impact of SFG on student‐teachers’ professional development in a pre‐service second language teacher education programme in Argentina. Framed in teacher research and ecological perspectives, a tutor examined the perceptions of a group of student‐teachers during the course of an academic year in a mandatory SFG module which favoured content and language integrated learning (CLIL) and metalinguistic knowledge. Data were collected through student‐teachers’ evaluations, summaries of group discussions, coursework samples, and whole class discussions as inherent parts of the module dynamics. Student‐teachers’ perceptions indicated that SFG had a positive effect on content knowledge and pedagogical content knowledge.