"Research Findings": This study incorporates teacher vitality, efficacy, and engagement with lesson design practice in which teachers can particularly encounter challenges from technology integration that calls for design thinking. Using a structural equation modeling approach, this study explores the relationships among teachers' design thinking engagement (DTE), efficacy in two types of technological pedagogical content knowledge (TPACK) called pedagogical content knowledge (PCK) and technological pedagogical content knowledge (TPCK), and design vitality (DV). A survey containing measurements for teachers' DTE, PCK efficacy, TPCK efficacy, and DV was delivered to 408 Chinese early childhood teachers. Reliability and validity of the instruments were attained through confirmatory factor analysis. Results indicated that teachers' DTE was statistically significant in explaining teachers' perceived PCK and TPCK efficacy, as well as perceived DV. Teachers' perceived TPCK efficacy significantly predicts DV. However, no significant prediction was found for teachers' perceived PCK efficacy to DV. "Practice or Policy": To ensure teachers with character strength as designers who face technology integration challenges, it is important for teacher development program to highlight teachers' proximal processes as designers structured with emotional, cognitive, and behavioral processes that can be manifested through design activities of "Empathize", "Define", "Ideate", "Prototype", and "Test".