This quasi-experimental mixed-methods design explored the effect of structured digital knowledge training on teachers’ professional growth result of in-service EFL teachers in Iran. Sixty practicing teachers (gender-balanced) from Safir Language Academy branches were allocated to experimental (n = 30) and control (n = 30) groups, matched by demographic and baseline competence factors. The experimental group took part in an eight-week training on the basis of the DigComp 2.1 model, concentrating on five competency areas: information literacy, content creation, collaboration, safety, and problem-solving. Quantitative data were gathered through pretest–posttest digital literacy evaluation and TPD surveys, analyzed using paired-samples t-tests and ANCOVA. The findings demonstrated meaningfully significant success in digital knowledge and scores of TPD for those teachers in the experimental group (p < .01), with the largest progress in content creation, digital collaboration, and online safety. Socioeconomic background did not have any meaningful impact on skill gains, though qualitative interviews showed persistent infrastructural impediment for lower-socioeconomic Status (SES) teachers. Survey data revealed meaningful increases in confidence and willingness to adopt technology-oriented teaching, supported by qualitative themes of increased experimentation and peer cooperation. These results show empirical evidence that short-term, structured digital literacy programs can produce observable professional development and attitudinal transformation, especially when instruction is task-based, context-responsive, and supported by application opportunities. The study highlights the need for incorporating digital knowledge as a major element of TPD programs and for dealing with systemic access disparities to ensure sustainable implementation.