This study examined managerial coaching as a strategic human resource development practice and its effect on employee performance in Nigeria's banking sector. The paper upgrades an earlier coaching-efficiency framework by positioning coaching as a multidimensional workplace-development mechanism comprising task guidance, developmental feedback, mentoring support, and sustained supervisor-employee interaction. The study retained the reported descriptive survey design and sample of 120 employees drawn from selected commercial banks in Nigeria. A structured questionnaire was used, while descriptive statistics, Pearson correlation and regression analysis were applied. The reported results indicate strong employee agreement that task guidance, performance feedback and mentoring support enhance work outcomes. Coaching was strongly and positively associated with employee performance (r = .74). Regression results showed R² = .55, indicating that coaching accounted for 55% of the reported variation in employee performance, while the model was statistically significant (F = 42.76, p < .001). The study concludes that managerial coaching is not merely a corrective supervisory activity but a strategic human resource development practice capable of strengthening productivity, work accuracy, service quality, adaptability and problem-solving capability. It recommends institutionalized coaching systems, coach-development programmes for line managers, structured feedback cycles, mentoring arrangements, digital-work coaching and systematic evaluation of coaching outcomes.