Background: The Glasgow Prognostic Score (GPS), which consists of albumin and C-reactive protein (CRP), may predict overall survival (OS) in cancer patients. The aim of this retrospective analysis was to evaluate the clinical impact of the preoperative GPS on patients with resected early stage non-small cell lung cancer (NSCLC). Methods: 300 patients with curatively resected stage I NSCLC were followed-up for OS, recurrence-free survival (RFS), cancer-specific survival (CSS), and death from other causes. Results: 229 patients (76%) had a preoperative GPS of 0, and 71 (24%) a GPS ≥ 1. The three-year probabilities of RFS, OS, CSS, and death from other causes were 81%, 84%, 88%, and 96% in patients with GPS = 0, and 79%, 74%, 91%, and 82% in patients with a GPS ≥ 1, respectively. GPS ≥ 1 was significantly associated with a higher risk of death from other causes (p = 0.022), serving as an independent predictor of death from other causes (p = 0.034). Pathologically elevated CRP levels (CRP > 5 mg/L) were found in 91 patients (30%). The mean CRP level was 7.88 ± 15.80 mg/L (0.5–135.6 mg/L). Pre-treatment CRP level was significantly associated with coronary heart disease (p < 0.0001), histology (p = 0.013), tumor size (p = 0.018), tumor stage (p = 0.002), and vascular invasion (p = 0.017). Conclusion: The preoperative GPS predicts adverse survival outcomes in patients with resected stage I NSCLC.