Introduction <p>Despite the importance of physical exercise in preventing non-communicable diseases, a research gap exists regarding its predictors among civil servants in Ethiopia's South Wollo Zone. Few studies have used theoretical frameworks like the Extended Parallel Process Model (EPPM) to investigate threat, efficacy, and exercise behavior in this population. This study applied the EPPM in a mixed-methods design to assess these predictors. It provides insights into how perceived threat, perceived efficacy, and response efficacy influence behavior, combining numerical data with subjective experiences to comprehensively understand factors affecting exercise for NCD prevention in 2025.</p> Methods <p>A concurrent mixed-methods approach was employed in conducting the study, combining qualitative and quantitative research methods simultaneously between February 10–28, 2025, GC. The quantitative study employed a stratified sampling technique to select 422 study participants, while the qualitative study utilized purposive sampling with the rule of saturation. Data were collected using self-administered questionnaires. For the qualitative study, in-depth interviews were conducted with the assistance of an audio recorder and an interview guide, led by the investigators. Data completeness was verified, and it was collected and entered using the KoboTool software before being exported to Stata version 17 for analysis. Descriptive statistics were computed, and logistic regression analysis was used to assess the significance of the association between the outcome response of physical exercise for NCD prevention and independent variables. Variables with a p-value less than 0.05 were considered predictors of outcome response of physical exercise in preventing non-communicable diseases, and the adjusted odds ratio with 95% CI was used to determine the strength and significance of the association.</p> Results <p>The outcome response of physical exercise for NCD prevention revealed that less than half of the civil servants, 47.57% (CI: 42.66%-52.52%), were engaged in adaptive Danger Control. Key predictors of this protective outcome response were identified; self-efficacy (AOR = 2.18, 95% CI: 1.68, 2.83) and response efficacy (AOR = 2.48, 95% CI: 1.92, 3.20) were the strongest predictors of being in the Danger Control category. Conversely, a higher perceived severity of threat significantly reduced the odds of this adaptive exercise behavior (AOR = 0.43, 95% CI: 0.32, 0.58). Among socio-demographic factors, marital status was a significant predictor. Single civil servants had four times higher odds of engaging in regular physical exercise for NCD prevention compared to their married counterparts (AOR = 4.03, 95% CI: 1.32, 12.36). The qualitative exploration provided crucial context, revealing that the transition to protective physical exercise is primarily driven by a strong belief in one's capabilities and the solution's effectiveness, while overwhelming fear acts as a significant barrier.</p> Conclusions <p>This study found a lower proportion of civil servants engaged in preventive physical exercise for NCDs compared to previous studies. Self-efficacy and response efficacy were strong positive predictors of this adaptive behavior, whereas perceived threat severity was a significant negative predictor. Single civil servants showed higher exercise engagement than their married counterparts. Qualitative data revealed that protective behavior was driven by belief in personal capability and exercise effectiveness, while overwhelming fear of severity acted as a key barrier, explaining the counterproductive threat-behavior relationship. Interventions should build self-efficacy, demonstrate benefits, avoid fear-messaging, and implement supportive workplace policies for married staff.</p>