While the distinction between academic disciplines and school subjects has received some attention, the question of which subject matter content knowledge (CK) teachers need as a foundation for initial teacher development has been raised. In science education, Teacher-related Science Content Knowledge (TerSCK) has been conceptualized to model the version of CK appropriate for teacher development and the basis for Pedagogical Content Knowledge (PCK) development. This study aimed to explore the efficacy of a TerSCK-based intervention in enhancing the quality of preservice teachers' (PSTs') TerSCK inorganic chemistry as a case study. Following an explicit intervention, mixed methods were employed to collect data from 35 PSTs before and after the intervention. Data collected were participants' reflections and completed test scores using a validated TerSCK measuring instrument, with a corresponding grading rubric on a Likert scale of 1-4.This generated ordinal scores which were converted into person ability and item difficulty probability measures placed on the same latent scale using the Rasch statistical model. The reliability indices calculated for the person's responses and test items were found acceptable both before and after the intervention. The comparison of the mean scores of the person performance probability measures was calculated using the Wilcoxon-Signed Rank test which demonstrated a statistically significant improvement in the quality of the PSTs' TerSCK (z = -5.166, p < 0.001, r = 0.87). Additionally, qualitative data from the intervention further corroborated the enhancement in the quality of PSTs' TerSCK after the intervention particularly, in knowledge of interconnections and tensions. The study concludes by highlighting the implications for teaching in science teacher education and outlining new research directions on teacher professional knowledge for teaching science.