Throughout the last years, we have been able to experience one of the most significant economic disruptions in history: The Digital Revolution. In a world that becomes more and more digitalized, companies must get an understanding of the fundamental rules of doing business in the digitalized business world in order to be able to innovate effectively and succeed with their business. The purpose of this paper is to get an in-depth understanding on how the digitalization affected the dynamics of doing business, and what the necessary key components are according to the literature and interviewees to succeed as a business in the digital era. Our contribution to the theory is achieved by conducting a multiple-case study in which eight case companies were selected and interviewed via semi-structured interviews. Subsequently, a grounded analysis was conducted to identify the subjective success factors of the interviewees which resulted in five major themes which contribute significantly to a firm’s success. We came to the conclusion that the main success factors for Start-Ups in the digital transformation are: 1. Lean Approach to Customer Orientation, 2. Entrepreneurial Goals & Culture, 3. Participation in the Entrepreneurial Ecosystem, 4. Integration & Utilization of Third-Party Technologies, and 5. Acquisition of Capital for Business Growth.