Academic entrepreneurship has been one of the main research fields over the past 20 years, specifically due to the interest of policy makers in this topic. Initially, this interest focused on the creation of university spin-off (USO) firms; although given the new circumstances of the university and its context, there is a need to steer the research topic toward survival. This is because the simple creation of USOs, without their being able to survive or create value, is useless. This article focuses on one of the determining factors of the success of USOs, as measured by employment and sales growth: the influence of institutional- and ecosystem-level variables. Through a backward sequential process, our results show that the business size and the public support in the field of training and bureaucracy are the main elements that affect success.