The leader is considered to play key roles such as organization or management in promoting group creativity. Previous studies focused more on the psychological and behavioral characteristics rather than on the dynamic behaviors of leaders in group activity. In this study, two experiments were conducted to respectively explore the effects of emergent and elected leaders’ problem-solving related utterances and turn-taking in conversation on group creativity. The results of Experiment 1 showed that, for emergent leaders, none of the utterances about problem solving of leaders was different from that of followers and leaders’ utterances about retrospective summary were positively related to the appropriateness of group creativity; meanwhile, the frequency of turns of leaders was higher than that of followers and was positively related with the appropriateness of group creativity. The results of Experiment 2 showed that, for elected leaders, the utterances about problem analysis, strategy planning, control and reflection, and retrospective summary of leaders were more than that of followers and leaders’ utterances about viewpoint generation were positively related to both novelty and appropriateness, while the frequency of turns of leaders was neither different from followers nor related to the novelty and appropriateness. This study focused on the dynamic behaviors of leaders in interpersonal interaction and revealed the role of leaders in group creativity.