Baricitinib is considered a first-line treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected adult patients with an associated cytokine storm syndrome (CSS). Our objective was to compare rates of secondary infections and long-term outcomes of elderly and non-elderly patients who received baricitinib for COVID-19. We conducted a single-centre observational study between November 2020 and September 2023, focusing on hospitalized adult SARS-CoV-2 patients with CSS, categorized as elderly (≥ 65 years) and non-elderly (< 65 years). Enrolment, severity stratification, and diagnosis of infectious complications followed predefined criteria. Outcomes of all-cause mortality and rates of non-severe and severe secondary infections were assessed at 1-year post-treatment initiation. Kaplan-Meier analysis was performed for survival analysis. In total, 490 patients were enrolled (median age 65 ± 23 (21-100) years (years, median ± IQR, min-max); 49.18% elderly; 59.59% male). Elderly patients were admitted to the hospital significantly earlier (7 ± 5 days vs. 8 ± 4 days; p = 0.02), experienced a higher occurrence of severe COVID-19 (121/241, 50.21% vs. 98/249, 39.36%; p = 0.02), and required the use of non-invasive ventilation at baseline (167/225, 74.22% vs. 153/236, 64.83%; p = 0.03). At 1 year, all-cause mortality was significantly higher in the elderly subgroup (111/241, 46.06% vs. 29/249, 11.65%; p < 0.01). At 90 days and 1 year, rates of any severe secondary infection were also more prevalent among the elderly (56/241, 23.24% vs. 37/249 14.86%; p = 0.02 and 58/241, 24.07% vs. 39/249, 15.66%; p = 0.02). In conclusion, elderly SARS-CoV-2-infected patients experience a more severe clinical course, higher secondary infection rates, and increased risk for long-term mortality, regardless of immunomodulatory therapy.