Background: Sustained implementation of facility-level quality improvement (QI) processes, such as plan-do-study-act cycles, requires enabling meso-level environments and supportive macro-level policies and strategies. Although this is well recognised, there is little systematic empirical evidence on roles and capacities, especially at the immediate mesolevel of the system, that sustain QI strategies at the frontline. Methods: In this paper we report on qualitative research to characterize the elements of a quality and outcome-oriented meso-level, focused on sub/district health systems (DHSs), conducted within a multi-level initiative to improve maternal- newborn health (MNH) in three provinces of South Africa. Drawing on the embedded experience and tacit knowledge of core project partners, obtained through in-depth interviews (39) and project documentation, we analysed thematically the roles, capacities and systems required at the meso-level for sustained QI, and experiences with strengthening the meso-level. Results: Meso-level QI roles identified included establishing and supporting QI systems and strengthening delivery networks. We propose three elements of system capacity as enabling these meso-level roles: (1) leadership stability and capacity, (2) the presence of formal mechanisms to coordinate service delivery processes at sub-district and district levels (including governance, referral and outreach systems), and (3) responsive district support systems (including quality oriented human resource, information, and emergency medical services [EMS] management), embedded within supportive relational eco-systems and appropriate decision-space. While respondents reported successes with system strengthening, overall, the meso-level was regarded as poorly oriented to and even disabling of quality at the frontline. Conclusion: We argue for a more explicit orientation to quality and outcomes as an essential district and sub-district function (which we refer to as meso-level stewardship), requiring appropriate structures, processes, and capacities.