This study aimed to identify the strategy types employed by firms during two periods—1981-1983 and 1984-1986—which exhibited different industrial structural characteristics in the Korean computer industry, and to investigate how the relationship between strategy types and firm performance changed with the environment. The analysis of 54 firms manufacturing computer hardware revealed the following: First, top executives perceived that the environment had changed dynamically between the two periods. Four and five strategic groups were identified in each of the two periods, respectively, and their characteristics were similar to the generic strategies advocated by scholars from advanced countries such as Porter and Miller. Regarding the relative performance of these strategic groups, the "cost leadership" strategic group showed superior performance in the first period when environmental characteristics were more stable, whereas "differentiation" strategic groups demonstrated superior performance in the second period when environmental characteristics were dynamic. Additionally, this study observed the interesting finding that in the first period, when the government exercised some control over the domestic market and the degree of competition among firms was low, the "stuck-in-the-middle" type exhibited even higher profitability than the generic strategies.