We show that early joiners|non-founder employees in the rst year of a startup| play a critical role in explaining rm performance. We use administrative employee- employer matched data on all US startups and utilize the premature death of workers as a natural experiment exogenously separating talent from young rms. We nd that losing an early joiner has a large negative eect on rm size that persists for at least ten years. When compared to that of a founder, losing an early joiner has a smaller eect on rm death but intensive margin eects on rm size are similar in magnitude. We also nd that early joiners become relatively more important with the age of the rm. In contrast, losing a later joiner yields only a small and temporary decline in rm performance. We provide evidence that is consistent with the idea that organization capital, an important driver of startup success, is embodied in early joiners.