Providing and assessing high-quality professional development can support teachers in implementing technology-delivered interventions that promote student self-determination and goal attainment. Still, there is limited research on teachers' knowledge, skills, and use of technology-delivered, self-determination interventions, such as the Goal Setting Challenge (GSC) App. The purpose of this convergent mixed-methods study was to evaluate qualitative and quantitative data collected from secondary special education teachers during a pilot study of the impact of the GSC App on student with disabilities goal attainment outcomes. Integration of our quantitative and qualitative data confirm, disconfirm, and expand our findings in that teachers felt the GSC App, a technology-delivered self-determination intervention, was an effective method for supporting student goal setting and delivering self-determination instruction via technology to students with disabilities. Teachers felt it was useful to have an alternative to teacher-delivered self-determination instruction. Limitations and implications for future research and practice are discussed.