Not only are policies negotiated and modified constantly at different levels, but also their outcomes are dependent on a range of contextual circumstances, such as forces of structure, local culture and agency. Policy implementation is a complex process; it involves groups of agents—situated at different levels within a stratified social realm—interpreting and responding to policy, and such engagements often produce both intended and unintended outcomes. Similar to any other policy implementation endeavor, “language planning is a process rather than a state of affairs… [it is a] continuous activity of controlling language variation under changing societal conditions” (Haarmann, 1990, p. 106). Using Singapore as an example, language policy and planning (LPP) has been a relentless task for the Singapore government since the introduction of its bilingual policy in 1966. The main aim has been to ensure that Singaporeans use and speak ‘proper English’. Policy planning at the macro level is often large-scale and systematic and, in the case of Singapore, it usually involves the macro agents, such as government and the Ministry of Education (MOE), which specifies the planned actions to be carried out at the national and local levels. However, at the local level, micro language planning takes a more diverse form. At this level, a number of different micro agents, including the community, schools (school leaders and teachers), family and students, play an important part in interpreting and responding to the policy directives. Drawing data from a funded project titled “Investigating Leadership and Policy Implementation for School Improvement” from Singapore, this chapter argues that in the educational domain, school leaders play a critical role in policy implementation, because they have the power to influence teachers’ self-efficacy and job satisfaction (Spillane et al., 2002), and this affects the ultimate outcomes of policy and LPP processes. This chapter discusses how at the micro level school leaders act as agents of change who have the power to decide how to react and respond, and what local structures are needed to support (or hinder) policy change in their schools. It focuses on school leaders’ ability to formulate supportive smaller school policies and communicate the objectives and expectations of LPP to their teachers, processes that often determine policy success. The chapter concludes by defining Singapore school leaders as ‘bounded’ agents of change who play a critical role in aligning LPP at both macro and micro levels, contextualizing it to the needs of the schools and explaining its purpose to the teachers. This conclusion is based on awareness that the extent of change is very much determined by wider structural, political and social forces.