School counselors are critical intermediaries in K-12 schools who can help students from undocumented immigrant families persist in school. Yet, a dearth of research exists about their advocacy work, or the range of efforts they make to support unauthorized youth. This paper asks, (1) what challenges do counselors face and strive to overcome to promote undocumented students' persistence in school?; and (2) what strategies do counselors use to encourage students to persist? Data come from an embedded case study with seven school counselors and a family intervention specialist in two Texas school districts on the U.S.-Mexico border. The findings revealed that two of participants' biggest challenges in terms of student persistence--and their strategies to help--related to complexities arising from students commuting across the border to school and students' transient living situations. Despite participants networking on behalf of students and families, forming partnerships and seeking services for students and families, counselors recognized limits to their efforts. Policies impeded their assistance, and events that were out of their control inhibited them from potentially acting as empowering agents for students in critical ways. While counselors can develop strong, trusting school-student partnerships to encourage student persistence, more research must explore how school leaders can act as empowerment agents and build capacity to serve newly arrived or undocumented families.