<p>This study investigated the degrees of (mis)alignments between the professed beliefs and observed in-class actions of an experienced science teacher regarding using question-asking as a primary instructional tool. Prior research encountered methodological challenges, relying on self-reports without systematic observation. To address this, this single case study employed various data triangulation strategies, such as in-depth interviews, member-checking interviews, and video recordings, to analyze belief-action relationships comprehensively. Various talk-based parameters were scrutinized, including the source of questions, structural qualities of questions, discourse functions of questions, cognitive demands of questions, and interaction patterns. Findings revealed notable disparities in the participant’s professed beliefs and practical implementation, particularly in question sources (teacher vs. student), discourse functions (questions for evidence-based reasoning, joint thinking, contextualizing, challenging, monitoring), and cognitive demands (applying, analyzing, evaluating, creating). Moderate divergences were identified in the science classroom’s structural attributes (open-ended vs. closed-ended) and contingency questioning conditions (contingent vs. non-contingent). Consistencies and incongruities were explained through science teachers’ intuitive thinking and deliberative reasoning in exhibiting a pedagogic vision or instructional noticing for their question-asking. Educational recommendations are provided, emphasizing the re-training of science teachers as deliberative, reflective practitioners.</p>