To address the pressing challenge of effectively managing multinational corporations' (MNCs) global sales forces, we offer a theoretical framework and investigate the effects, across cultures, of particular sales manager practices on sales manager effectiveness (SME). Further, we examine whether high SME is associated with salesperson commitment, regardless of national culture. The model is tested on survey responses from 888 salespeople from Canada, Mexico, the United States, China, Australia and New Zealand. The results reveal that national culture moderates most antecedents' relationships to SME. For example, masculinity weakens the positive effect of fixed compensation on SME, supporting the expectation that salespeople in highly masculine countries are more driven to achieve material rewards through greater variable pay. Collectively, study results suggest cultural conditions where managerial practices should be prioritized. SME has a universally positive effect on salesperson commitment, reinforcing the thesis that adapting sales manager practices across countries to optimize SME provides a tangible advantage.