This study describes a Program to Strengthen Cognitive and Socio-Emotional Skills (PCSES) applied by teachers to their initial-level students during the COVID-19 pandemic. This work has two objectives. The first is to explore the grade of acceptance of teachers regarding the training process on cognitive and socio-emotional skills carried out by our team during the COVID-19 pandemic period, according to the school context, urban vs. urban-marginal. The second is to analyse whether teachers perceived improvements in the cognitive and socio-emotional performance of their students after the implementation of the PCSE, according to the school context. The sample consists of 36 initial-level teachers, in charge of classrooms of 4-year-olds and 5-year-olds. During the pandemic, 2020-2021, 36 teachers responded to the survey: 20 teachers from urban schools, and 16 teachers from urban-marginalized schools located in socially-vulnerable sectors. Despite the difficulties experienced during the pandemic, 94.45% of the teachers indicated that they were satisfied with the training process received. In addition, teachers from both school contexts perceived improvements in the cognitive and socio-emotional performance of their students after the implementation of the PCSES. These results suggest that the training of initial education teachers made it possible to implement a stimulation program during the pandemic period that aimed to favor cognitive, emotional, and social functions in students. The main contribution of this work was to increase the evidence of the importance of teacher training and knowledge for the development of strategies that can be used to scaffold socio-cognitive and emotional processes in the context of teaching-learning.