Digital competence is crucial for technology integration in education, with teacher educators playing a vital role in preparing student teachers for digitalized environments. In our conceptualization of teachers' digital competence (TDC), we emphasize its embeddedness in a professional context. The Digital Competence for Educators (DigCompEdu) framework aligns with this understanding, yet research focusing on teacher educators is limited. To address this gap, we followed a quantitative research strategy to explore different sources of validity evidence for the DigCompEdu in a small, non-representative Hungarian teacher-educator sample (N = 183) via an online questionnaire. Our study, regarding the DigCompEdu as a measure of TDC, aims to (1) establish validity evidence based on internal structure concerns via Partial Least Squares structural equation modelling to evaluate the validity and reliability of the tool, (2) compare TDC self-categorization with test results to provide validity evidence based on the consequences of testing, and (3) explore validity evidence based on relationships of TDC with other variables such as age, technological, and pedagogical competence. Our findings reveal a significant mediating effect of professional engagement on teacher educators' ability to support student teachers' digital competence development. Despite the sample's limitation, this study contributes to refining the DigCompEdu framework and highlights the importance of professional engagement in fostering digital competence among teacher educators.