Background: Chronic suppurative otitis media (CSOM) is a common condition treated with tympanoplasty, though the role of cortical mastoidectomy in improving outcomes remains unclear. The aim of the study is to evaluate the role of cortical mastoidectomy in tympanoplasty for patients with persistent or intermittent discharging chronic suppurative otitis media (CSOM) and to identify factors influencing surgical outcomes, particularly graft uptake and hearing improvement. Methods: This prospective was conducted at the Department of ENT, GMC Udhampur, Jammu randomized, controlled study included patients diagnosed with persistent or intermittent discharging CSOM. Patients were randomly assigned to undergo tympanoplasty alone or tympanoplasty with cortical mastoidectomy. Hearing outcomes, specifically air-bone gap closure, and graft uptake success rates were assessed and compared between the two groups. Results: At 12 months postoperatively, both groups showed significant improvement in air-bone gap (ABG), with no significant difference between Group A (11.93 ± 4.54 dB) and Group B (12.24 ± 3.89 dB) (p = 0.689). The success rate was 81.7% for Group A and 75% for Group B (p = 0.375). In univariate analysis, key predictors of success included a dry period of ≥3 months (87.3% vs. 65.3%, p = 0.004) and normal contralateral ear status (88.4% vs. 64.7%, p = 0.001). Smoking was associated with lower success (65.6% vs. 83%, p = 0.041). Multivariate analysis identified a dry period of ≥3 months as the most significant predictor (OR = 2.73, p = 0.007). Conclusion: Cortical mastoidectomy does not confer additional benefit when performed alongside tympanoplasty in cases of persistent or intermittent discharging CSOM. Satisfactory surgical outcomes can be achieved with tympanoplasty alone. Preoperative factors, particularly a dry ear period longer than three months, play a crucial role in optimizing graft uptake and surgical success.