Party members are important assets to a political party, for without their help in running the daily affairs and campaigns, a party cannot be seen to exist. Therefore, there is no doubt that the party members are important. By analyzing data from in-depth interviews with central and local party branches, as well as questionnaires directed at party workers, this article aims to examine who the party members of the Kuomintang (KMT) are. Why do they join the party? What is the level of involvement of the members. The data reveal that KMT membership has been increasing steadily over the past decade, which indicates the KMT’s capacity to draw support from voters. In general, KMT members tend to be older than the electorate on average, and most of them are male, reflecting that gender and age gaps exist between the KMT members and the electorate. While many KMT members are motivated by the party’s ideas and issue orientations, to some extent, solidary incentives and material incentives also play a role in recruitin new members. The level of activism varies among the different local branches, with different degrees of participation in terms of age, region, and the party’s political strength being found. Members in rural areas participate more than those in the cities, while older members participate more than the others. Members also participate more if the KMT retains a dominant status at the national level or in the local districts.