The start-up has overgrown in Indonesia. Although Indonesia is famous for its five unicorn Gojek, Tokopedia, Traveloka, Bukalapak, and Ovo, the total success rate of Indonesian start-up is only 5 percent. One of the reasons is the lack of high quality of human resources. The fact that millennials dominate the current workforce, it creates challenges for new enterprises and human resource managers in managing this unique generation. They have a unique nature in terms of performance in the workplace. Therefore, this research aims to analyze the effect of work environment, leadership, team & co-worker, and compensation on employee engagement. Also, the effect of employee engagement on employee performance of millennials uses the Structural Equation Modeling (SEM) Partial Least Squares (PLS) testing in start-up companies in Jakarta. This research was carried out using a quantitative approach to 100 respondents in several companies in Indonesia. This research involves the empirical investigation of observable and measurable five variables that were accepted and rejected. Based on this research, the researcher found that the work environment and leadership behavior do not significantly influence employee engagement. Meanwhile, team and co-workers and compensation have a significant influence on employee engagement. Therefore, it is found that employee engagement does have a positive and significant effect on variable employee performance.

Keywords: Employee Engagement, Employee Performance, Millennials, Start-up, Work Environment