In this paper we examine the microprocesses associated with a successful business established by two young brothers (16 and 18). The study is informed by recent processual approaches to entrepreneurship associated with effectuation theory and sensemaking. We also draw on literature related to personal dispositions, which are the basis of habitual behaviours. The empirical data are drawn from a longitudinal study of an unconventional family business which was created by the two brothers while still at school. Opportunities were created, rather than discovered, by optimizing limited familial resources during the early stages of start-up. We expand effectuation theory by demonstrating the role of sensemaking (enactment, selection and retention), familial influences on dispositions (habits, heuristics and routines) and experiential learning during the first three years of operation.