The purpose of the study was to investigate factors affecting the career satisfaction of vendors’ employees who perform project tasks on-site at clients’ owned facilities for several years as part of project delivery in Sri Lanka. The study identified six factors that influence the career satisfaction of these employees, namely, work content, financial rewards and other gains, work relationships, supervisor support, general working conditions, and opportunities experienced due to being stationed at clients’ firms. Overall, the study context is novel and the findings make contributions to the advancement of project management literature and practice.