Chronic insomnia is a frequent presentation in primary care and often results in referrals to psychiatry or neurology. However, behavioral and environmental determinants—specifically sleep hygiene disturbances—are highly prevalent yet commonly underrecognized. Early detection of sleep hygiene problems can prevent unnecessary pharmacologic treatment and reduce the need for specialist referrals.A 38-year-old man presented with persistent insomnia and daytime fatigue despite previous neurological and psychiatric evaluations and two unsuccessful medication trials. A structured sleep history explored bedtime routines, wake time variability, screen exposure, caffeine intake, stress, and environmental conditions. A sleep diary demonstrated irregular sleep–wake cycles, smartphone use shortly before bedtime, caffeine intake after 17:00, cognitive hyperarousal related to work stress, and a bright, noisy bedroom environment.This case demonstrates chronic insomnia driven primarily by modifiable sleep hygiene disturbance, underscoring the diagnostic and therapeutic value of primary care in identifying behavioral determinants before initiating sedative–hypnotic medication or referring to specialist services.Sleep hygiene disturbance is a common and modifiable cause of chronic insomnia. Comprehensive lifestyle and environmental assessment in primary care can reduce unnecessary specialist referrals and medication use. Behavioral management—including patient education, sleep diaries, and stress-reduction strategies—can yield significant improvement.The findings of this case demonstrate that sleep hygiene disorder can be a sufficient underlying mechanism for chronic insomnia, echoing international evidence. Guidelines from the American Academy of Sleep Medicine and the European Sleep Research Society recommend behavioral and sleep hygiene interventions as first-line therapy, often matching or surpassing pharmacologic treatment in long-term outcomes. Studies consistently identify irregular sleep–wake schedules, evening screen exposure, late caffeine intake, and cognitive hyperarousal as prevalent contributors. The present case reflects a common pattern described in the literature: prior specialist evaluations and medication trials occurred before lifestyle factors were explored. Successful symptom resolution through a holistic primary care strategy reinforces the need to incorporate detailed behavioral and environmental sleep assessment into routine insomnia management.A holistic approach in primary care that prioritizes sleep hygiene, lifestyle modification, and environmental optimization can significantly improve chronic insomnia. Early recognition and patient-centered education empower individuals to manage symptoms effectively and minimize reliance on medication-based approaches.