The main purpose of this study is to investigate the determinants of employee performance: mediating role of engagement in the case of Ylmana Densa Woreda public sectors. This study depends on the data gathered from the public sector employees in Ylmana Densa Woreda. The study used a quantitative research approach and explanatory research design. The data used in the study was primary data collected from the respondents through Five-point Likert scale questionnaires. The scope of the study was delimited to all Ylmana Densa Woreda public sector employees with geographically and conceptually independent variables were training, leadership style, and PM, the mediating variable was engagement, and the dependent variable was employee performance. Based on the stratified random sampling technique, from the total population, 211 respondents were selected and 205 returned well-filled questionnaires were analyzed through the aid of SPSS software version 26, and the mediation analysis was made through Amos graphics software version 23. Descriptive statistics, correlation, regression, and mediation analysis were done through the above two computer software. Based on the analysis result training, leadership style, and PM predict employee performance 51.7% variation and training had a positive and significant effect on employee performance (β=.297, p=.000), leadership style had a positive and significant effect on employee performance (β=.303, p=.000), and similarly, PM also had a positive and significant effect on employee performance (β=.221, p=.001). In addition to this, the mediating variable engagement had a positive and significant effect on employee performance (β=.765, p=.000). On the other hand when the mediating variable engagement added to the model those independent variables and engagement collectively predict employee performance 63% variation and the mediating variable engagement had a full mediation role on the relationship between training and employee performance (β=.168, p=.003) as well as full mediation role on the relationship between leadership style and employee performance (β=.198, p=.002) whereas engagement partially mediates the relationship between PM and employee performance (β=.085, p=.019).