This study investigated the theoretical underpinnings of individual differences in emergent leadership behaviors and their relationships to teamwork processes and outcomes. Both personality and cognitive ability were utilized to examine behaviors of leadership emergence, team performance, and KSAs. Three hundred and twenty undergraduate psychology students completed personality and cognitive ability tests and then formed sixty-seven mixed-gender teams. Members rated each other on emergent leadership behaviors as well as their team on specific interpersonal and self-management KSAs. Results revealed that extroversion, openness to experience and cognitive ability were predictive of emergent leadership behaviors. Conscientiousness and cognitive ability were associated with team performance. Implications and future directions for research are discussed.