Against the trend of declining entrepreneurial intention at a higher (third) age but in the light of its extensive economic and societal advantages, Sweden has faced an increasing number of seniors starting businesses in recent years. Besides environmental factors, academia identified but practice neglected to adequately consider inherent factors as triggering senior entrepreneurship and therefore this thesis has investigated in-depth, what motivates those involved individuals. Research questions of this study where how the emergence of senior entrepreneurship can be described, how motivation of senior entrepreneurs beyond the theory of planned behavior can be understood and theoreticized and what the implications for the emergence of senior entrepreneurship motivation are. For answering these questions, case studies of nine senior entrepreneurs, primary based on semi-structured interviews, were presented and analysed in an abductive, qualitative study. Findings show that the emergence of senior entrepreneurship can be described from different perspectives and that individual reasons to start a business later in life vary. As further identified, the interplay of three themes constitutes a theoretical motivation framework for senior entrepreneurship: Events, backgrounds and desires. Whereas events, often as the start of retirement, unemployment or failing health trigger the choice of senior entrepreneurship, certain distinct backgrounds of the seniors such as education, work experience, wealth, family and social networks channel effort in the intention and behavior towards entrepreneurial activity. These factors can be further described by using the theory of planned behavior (TPB) but also enrich this theory in turn. Finally, and as the main contribution of this thesis to theory, the persistence of motivation is influenced by two major themes in the form of desires for ”preservation” and ”enhancement”. These forces drive senior entrepreneurs to maintain and/or improve their individual levels of lifestyle satisfaction at a higher age, influenced by sought after states of health, wealth, social inclusion and responsibility, personal development, and fulfillment, etc.. Across the range of these motivational elements of events, backgrounds and desires, attempts to stimulate senior entrepreneurship motivation can focus on a closer attendance in individual life situations, shape supportive background contexts or arouse interest by emphasizing that and how senior entrepreneurship can generate satisfaction in life.