For this study, a questionnaire survey was administered to 824 people who had been posted overseas for at least one year (657 of whom had been involved in a business for the overseas market) in order to explore the factors behind the success of an overseas business. The results made clear, on one hand, that if Japanese companies focus on an overseas business, by, for example, defining the objectives and roles of the business, investing in market research, and posting core personnel abroad, they reach desirable outcomes, but, on the other hand, those outcomes are adversely affected when companies define the objectives and roles prior to conducting market research. A focus on overseas business increases personnel’s organizational identification with his or her headquarters and with the overseas business unit. However, dysfunction occurs when personnel feel high organizational identification with the overseas business unit, and that they are not expected to show customer-oriented behavior. According to our additional analyses, this dysfunction of organizational identification emerges when one perceives a weak identity of one’s organization.