It is increasingly recognized that agency plays an essential role in shaping language-in-education policy (LEP) and influencing the learning process. Research on agency has not yet adequately engaged with the field of heritage education and maintenance in diasporas. Drawing on Shohamy's and Bonacina-Pugh's conceptualization of declared, perceived, and practiced language policies, we examine the individual agency of three groups of actors--people with power (principals), people with expertise (teachers), and people with interest (students)--in a variety of policy or planning activities within two Chinese heritage language (CHL) schools in Brussels. On the basis of collected ethnographically informed data in conjunction with the conversation analysis of audio-recorded classroom interactions, our findings illustrate how three types of agentive roles are effective in forming language policies and constructing discursive spaces within the CHL schools, with a clear orientation shift from monolingualism to multilingualism. This study contributes to research on heritage language maintenance in a highly multilingual, diasporic, and educational context by providing a portrait of how educational practitioners and learners assert their agency to explore locally appropriate language policies that maximize actors' potential to teach and learn heritage languages.