When given opportunities for personal glory in individual settings, people high in narcissism excel. However, less is known about narcissists’ influence in team contexts. Across two studies (utilizing cross-sectional and two-wave longitudinal designs) involving 706 athletes from 68 teams in total, we tested a conceptual model linking narcissism to task cohesion, via intragroup conflict, moderated by narcissistic group composition. We tested a new sports-oriented measure of intragroup conflict using Bayesian estimation and evaluated our theorizing using a multilevel conditional indirect effect hybrid model. Across both studies, we found that narcissism influenced perceptions of task cohesion via process conflict only; with a negative influence at low narcissistic group composition that was weakened (Study 1) or nullified (Study 2) at high narcissistic team composition. Collectively, these findings offer the first example of how narcissism influences task cohesion in team settings and the contextual effects of narcissistic group composition.