Motivation is a significant concept within the entrepreneurial process, referring to everything from identifying opportunities and generating or articulating ideas to evaluating opportunities and planning steps to form or launch an enterprise and then grow and develop that enterprise. Motivational drivers can be classified as non-affective (i.e., rational and calculative) and affective (i.e., emotionally laden). The present doctoral thesis focuses on affective motivation among entrepreneurs and is comprised of four papers. Collectively, these papers focus on two research inquiries: (1) the role of social and cognitive factors for the development of affective entrepreneurial motivation and (2) how and why affective entrepreneurial motivations are related to entrepreneurial activities. Specifically, the thesis papers examine the following topics:Paper I. Entrepreneurship Psychology: A Review. This paper addresses the status of extant research in key areas of entrepreneurship psychology (personality, cognition, emotion, attitude, and self within entrepreneurs’ psychology) and what can be anticipated from future research in this domain. It draws upon a literature review and expert panel survey.Paper II. Exploration of Motivational Drivers towards Social Entrepreneurship. This work explores what drives individual motivation for engagement and persistence in social entrepreneurial activities. It builds on a qualitative, multiple case study. Paper III. Committed to a Cause: Passionate Leader Behavior in Social Enterprising. This qualitative, multiple case study explores the question of how passionate leader behavior benefits social enterprising.Paper IV. Obsessive Passion, Competence, and Performance in a Project Management Context. This study tests the links among competence, passion and how entrepreneurial projects are led. It builds upon quantitative survey data