In times of exogenous shocks, challenges encountered by start-ups are more dynamic than established corporations. From the onset of the pandemic, the number of start-ups either succeeding or failing in these competitive times have been unprecedented, with many becoming unicorns, while many others have shut down. In this volatile atmosphere not just success, but even survival of start-ups rests solely on the leader. Leading them through the global turmoil is wrought with intangible parameters. The right leadership style is essential to spearhead the start-up in any eventuality. Apart from the leaders of start-ups considered in the study, it has been found that even employees have been adversely affected by the pandemic. From the stress of handling work in these trying times, the employees are also experiencing an uncertain future, dependent on the economic health of the start-up. It is imperative to understand what can be done to improve the mental health of employees working in STEM start-ups. Authentic leadership and servant leadership styles have been studied in various contexts. A unique contribution of this article is the impact of the managers adopting a combination of these two highly effective leadership styles. Identifying new nuances in existing leadership research is especially critical so it could be practically adopted by managers in the present VUCA world. In this descriptive study, 586 employees working in STEM start-ups ranging from manufacturing, engineering and technology are chosen for the study. The impact of authentic leadership style on the employees’ burnout is studied while the trust in supervisor is studied in a mediating role. The empirical evidence shows that presence of authentic leaders in a start-up would lead employees experiencing reduced workplace burnout. Supervisor trust partially mediates this relationship between authentic-servant leadership and employee burnout. This study stresses on the importance of supervisor trust in reducing employee burnout. In times of uncertainty, when the leader is authentic in his or her transactions with the employees, it would go a long way in boosting their morale. This study is one of the first to identify the effectiveness of combining two leadership styles and it contributes to the leadership research in studying the triage of factors namely employee burnout, trust in supervisor and authentic-servant leadership in a start-up climate. The author concludes by charting out a detailed future agenda for attuning authentic-servant leadership practices towards sustainability of start-ups.