This article shares what was learned from the feasibility assessment of a nurse-led school-based active surveillance (SBAS) pilot to track chronic absenteeism using myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as an exemplar. This pilot encompassed a 3-year period with training and feedback from school nurses (SNs) on data collection and ME/CFS. SNs found that the SBAS process helped them effectively identifying undiagnosed conditions. The assessment revealed the importance of focusing outreach efforts and establishing relationships with the school leadership in developing health policies and programs in the school setting. The pilot data were used to develop a manual to guide SNs for the SBAS process. This can be viewed as a model for SNs in establishing a surveillance to identify and track conditions like ME/CFS. With overlapping symptoms of Long COVID to ME/CFS, this assessment may provide insights for additional efforts to understand the impact of Long COVID on students' education.