This study investigates the role of Professional Development (PD) programs in supporting public school teachers in the Philippines to implement the Most Essential Learning Competencies (MELCs) amidst the COVID-19 pandemic. The dramatic shift to distance and modular learning placed acute challenges and called for educators to adjust their skill sets with very little lead time. Using a mixed-methods approach, data was collated from 300 teachers through surveys and interviews. Results indicated that technology and instructional adaptation-focused PD programs were significantly related to improved teacher self-efficacy and fidelity to MELCs. Barriers of limited technological access and a lack of continued support were also noted. This article speaks to the importance of focused PD in educational reform and provides lessons learned with future implications to promote sustainability. These findings will improve the understanding of professional development programs in closing the gaps between educational needs in crises and support teachers in delivering quality teaching.