One of the main purposes of technology integration was for effective teaching and learning. The model of technological pedagogical content knowledge (TPACK) was the suggested framework that could be applied in different facets of the teaching and learning process. Information communication tools (ICT) are the common infrastructures used for this process, and studies of TPACK application were mainly focused on normal desktop computers, and at the university level. However, there were uncommon studies of smart technologies such as SMART Board and SMART Notebook software at the secondary level, concerning TPACK applications. Against this background, the present study evaluated secondary school teachers on the TPACK applications in smart classrooms, as well as its effect on students' performance in chemistry. Through explanatory sequential mixed method design, results were highlighted and interpreted. These included lesson observation for quantitative data on four categories of knowledge: content knowledge, technological knowledge, technological pedagogical knowledge, and pedagogical content knowledge and students' performance in chemistry. While qualitative data about views were thematically analysed into strengths and challenges, as well as suggestions regarding TPACK applications and improving teaching and learning. The study involved seven teachers and 142 students, who were selected using a convenient sampling technique. The results revealed that teachers demonstrated the capacity to connect all categories of knowledge, develop, and conduct teaching where technology, pedagogy, and content interact. However, as the observed teachers acknowledged, it is challenging to overcome traditional teaching methods. This is due to several external factors, most notably the limited availability of digital equipment, and inadequate technology training, among others, which can improve the TPACK applications and promote students' engagement and learning. Further, the result of the intervention showed that teachers need continuous professional development, as it reflects significantly (p ?0.05) on students' performance in chemistry. These findings could serve as a foundation for creating policies that prioritise allocating funds to public schools for educational technology tools that will help teachers and students improve the teaching-learning process.