Entrepreneurship has emerged as a key vector, introducing dynamism in stagnant markets, through technological change, innovation, and process restructuring. However, despite all the potential benefits, this is a very arduous and uncertain process, to the extent that many of the companies created end up failing in the first five years of activity. This chapter aims to study the entrepreneur as an individual, focusing on the analysis of their personal characteristics and their impact on the growth of the new created firm. A mixed methodology was developed to test which personal characteristics impact growth. A questionnaire was carried out on a sample of 87 Portuguese entrepreneurs and, additionally, 10 interviews were held with the purpose of complementing the information of the collected data with a qualitative approach and a more personal perspective. Finally, the results revealed that there are certain characteristics that enhance and influence the growth of startups, the most crucial being leadership, the need for achievement, proactivity, and resilience and adaptability.