In this research, we aimed to explore determinants of job performance and well-being while working from home (WFH) in a specific context of mandatory WFH during COVID-19 lockdown in Croatia, a country where WFH is a highly unusual arrangement. In Study 1, on a nationally representative sample of 166 Croatian employees WFH during lockdown, we tested if aspects of work-life balance (WLB) – work-to-family and family-to-work conflict, time structure of the work day and psychological detachment from work – would predict job performance and well-being. We showed that of the four WLB aspects, only time structure was important both for job performance and well-being. In Study 2, we used a convenient sample of 575 Croatian employees who were WFH during lockdown to investigate conscientiousness, emotional stability and autonomy at work as drivers of the WLB during WFH, and to constructively replicate Study 1 findings using different and more advanced measures. Findings showed that autonomy, conscientiousness and, especially, emotional stability contributed to the WLB and were important for job performance and well-being. WLB, especially time structure, predicted both job performance and well-being, and enhanced time structure mediated the effects of personality traits and autonomy on both outcomes.