The importance of customer relationships and the active use of customer relationship management strategies have been emphasized as important marketing concepts. However, questions about the effectiveness of the customer relationship management strategy have also been continuously raised, and it has been recognized that there is a lack of clear criteria for how it works. Based on the empirical data, this study compares the performance of the customer relationship management strategy based on the factors of the competitive market and theoretically identifies its differential effects, providing practical implications for the effective implementation of the firm's customer relationship management strategy in the competitive market. Specifically, this study identified customer relationship management strategies between customer acquisition strategies and customer retention strategies and quantified them into customer equity to demonstrate their impact on firm performance. In addition, the impact of market growth and competition structure(Leader vs. Follower) were compared and analyzed as key factors among market environmental factors that could affect customer relationship management. The analysis revealed a significant differential effect of the customer relationship management strategy based on market growth and competitive structure. First, in general, the effectiveness of customer retention strategies for a leader is superior to the effectiveness of customer acquisition strategies, similar to the traditional view of customer relationship management strategies. Second, the effect of customer retention strategies on a leader appears to be superior to market growth in maturity, indicating that the effects of both strategies change dynamically according to market growth. Third, unlike the traditional view of customer relationship management strategy, the effectiveness of the customer retention strategy for a follower was not superior to the effectiveness of the customer acquisition strategy. Fourth, the relationship between the customer acquisition strategy and the customer retention strategy effect for a follower was a major dynamic change with the market growth. In other words, it has been shown that the customer retention strategy has a great effect in the growth phase, while the customer acquisition strategy has a greater effect in the maturity phase for a follower. The above results suggest that the customer retention strategy in the competitive market may not always be the best, as highlighted by traditional marketing theories, and rather, for a follower, the customer acquisition strategy may be a more effective competitive strategy. This study presents new results and implications for customer relationship management strategies in competitive situations.