The rapid digitalization of education demands that Indonesian language teachers strengthen their digital competencies, especially in developing L1 writing skills through innovative teaching strategies. This study examines the impact of a community-based professional development program centered on Padlet integration for Indonesian language instruction. Utilizing a convergent mixed-methods action research design, 29 senior high school teachers in Pekanbaru, Riau Province, participated in a two-day intensive training, followed by six weeks of classroom implementation and ongoing mentoring. Data were collected through pre- and post-intervention assessments using the DigCompEdu Check-in instrument, lesson plan quality rubrics, classroom observation protocols, analysis of a student writing corpus (N = 472), and semi-structured interviews. Results indicated significant improvements across all measured outcomes. Teachers achieved notable gains in digital competence (ΔM = +12.83, p < .001, d = 1.24), lesson plan quality (ΔM = +2.23, p < .01, d = 0.67), and classroom implementation. Student writing performance also improved substantially (ΔM = +8.99, p < .001, d = 0.73), with increased lexical diversity, cohesion, and collaborative engagement. Qualitative data highlighted enhanced teacher confidence, ongoing peer collaboration, and improved pedagogical practices. The findings demonstrate that community-based Padlet training effectively elevates digital competence and transforms L1 writing instruction, offering empirical support for scalable professional development models that blend digital tools with pedagogical innovation in Indonesian education.