Modern teaching practices continually seek innovative methods to make learning more engaging and effective. This paper investigates the pedagogical potential of storytelling as a tool for teaching mathematics in first grade, focusing on the support that AI can provide to teachers when designing storytelling scenarios. Through a quasi-experimental study, a ten-hour teaching intervention was conducted, involving the use of two narratives. The first was created entirely by the teacher, while the second incorporated contributions from ChatGPT. The results from both quantitative and qualitative data showed that storytelling positively impacted students’ mathematical achievement, emotional engagement, and participation, with benefits varying according to their level of achievement. Additionally, the study found that AI significantly eased the process of developing pedagogically tailored materials. Hence, this research highlights the importance of integrating innovative storytelling techniques in primary school mathematics education, enhanced through technological assistance.