Security personnel are in most public high schools nationwide, a presence that has increased over the last several decades. While prior research has extensively studied the role of sworn school-based law enforcement, less work has examined the roles and responsibilities of non-sworn school security guards. Drawing on a national sample of school security guard job advertisements, this study leverages role and signaling theory to examine their articulated responsibilities and expectations. Descriptive analysis of job characteristics and qualifications along with content analysis of job descriptions reveals that security guards are expected to maintain safety through a security-oriented set of responsibilities. Security guards are often expected to engage in high-stakes situations--involving emergency response, student discipline, and interfacing with law enforcement--despite requiring relatively little formal educational or job-specific training. The findings are interpreted against a backdrop of prior literature and policy action that suggests a desire for school safety enhancements but a concern about the unintended criminalization of students.