Background: Days Alive and Out of Hospital (DAOH) is a recently introduced, readily obtainable postoperative outcome measure method that expresses procedure and disease-associated morbidity and mortality. In this study, we evaluated DAOH with 30- and 365-days follow-up periods after primary surgery (DAOH₃₀ and DAOH₃₆₅, respectively) for patients with oral cavity squamous cell carcinoma (OSCC). The aim of this study is to identify patient-, procedure- and disease-associated risk factors for patients treated with primary surgery for primary OSCC. Material and methods: This retrospective cohort study from a prospective collected database represents patients from Eastern Denmark surgically treated for primary OSCC in the period 2000–2014. DAOH₃₀ and DAOH₃₆₅ were calculated and associations with patient characteristics including comorbidity, tumor characteristics, clinical outcomes such as length of stay, readmission, and mortality were evaluated. Tests for difference and significance between groups were assessed with Mann–Whitney U test and quantile linear regression. Results: We included 867 patients (63% males, median age: 63 years (IQR 56–70 years)). Median DAOH₃₀ and DAOH₃₆₅ after OSCC surgery were 25 days (IQR 21–27 days) and 356 days (IQR 336–360 days), respectively. Alcohol consumption had a significant association with a lower DAOH₃₆₅, p < 0.01, but not with DAOH₃₀. Advanced T-stage, adjuvant radiotherapy (RT) and increased Charlson Comorbidity Index (CCI) score was significantly associated with a lower DAOH₃₀ and DAOH₃₆₅. Conclusion: In this population-based study in OSCC patients treated with primary surgery, we found that DAOH after 30 days was 25 days (83%), while DAOH after 365 days was 356 days (98%). Advanced T-stage acts as a predictor for significant DAOH₃₀ and DAOH₃₆₅ reduction while excessive alcohol consumption predicts a significant DAOH₃₆₅ reduction. Readmission within 30 days following surgery was associated with further readmission within one year.