Existing perspectives on normative and aspirational control have undertheorised how digital technologies such as digital self-tracking might alter what kinds of control is possible in the workplace. This article remedies this lack by studying the affordances of digital self-tracking in the workplace. Empirically, we draw on a case study of digital sleeptracking in relation to a well-being initiative in a private energy company, Encorp. Our analysis reveals how digital self-tracking affords body visibility and remote management but also creates affordance opacity and an ambiguous space of autonomy and control. We theorise how digital self-tracking in the workplace both enables new forms of aspirational control, and creates ambiguity and new limits to control. We conclude by discussing challenges and opportunities for future research on digital self-tracking in the workplace.