Are serial entrepreneurs – owners of multiple firms – important for understanding the sources and aggregate consequences of business dynamism? Using unique administrative data, we show that – compared to other businesses – firms of serial entrepreneurs are larger, more productive, grow faster, exit less often and disproportionately contribute to aggregate job creation and productivity growth. Moreover, even the very first firms of serial entrepreneurs feature these “premia”, suggesting an important role of innate abilities, rather than luck or learning. Finally, we show theoretically and quantitatively that serial entrepreneurship is also important for understanding and modelling of top income inequality.