This study investigates the process of relationship among past employee voluntary turnover rates, future employee voluntary turnover rates, and firm performance. In addition, we considered the remaining employees' organizational commitment as contextual factors (boundary condition) between past (t-1) and present (t) employee voluntary turnover rates. Although the roles and relationships of diverse factors regarding employee turnover at organizational level have been identified in the literature, few attempts have been made to address the relationship of turnover at two different points (e.g. past and present) in time. By noting on the social dynamics and turnover contagion model, we attempted to fill the research gap and shed light on the understanding of the socially dynamic nature of employee turnover. For empirical analysis, we utilized the Human Capital Enterprise Panel Survey and chose 1,239 observations and 469 companies from 2007 to 2017. By doing so, we conducted panel analysis using random-effects modeling based on year-lagged design. The results show that, first, there is a positive causal relationship between past turnover rate (t-1) and present turnover rate (t), supporting the contagion effect. Second, the present turnover rate (t) mediates the relationship between past turnover rate (t-1) and future firm performance (t+1). Third, organization-level organizational commitment, derived by summing up responses from multiple employees, moderates the relationship between past turnover rate (t-1) and present turnover rate (t) such that the positive relationship (contagion effect) is stronger when organizational commitment is low rather than high. Based on the results, we provided theoretical and practical implications which could help organizations enhance their productivity and effectiveness.