It is the aim of this study to explore the characteristics of influential peers identified by schoolmates, and the mechanism by which they exert their influence on their peers.

Adolescent crowds are a salient influence on the health-risk behaviors of peers, contributing to adolescent substance use such as drinking alcohol, smoking cigarettes, and taking drugs.

A mixed method study. Three schools granted us access to students and those who had been nominated as influential by their peers. The students were asked to nominate and indicated the characteristics of peers whom they considered influential in a quantitative study. Those peers whom they considered influential were invited to take part in focus group interviews. A total of six focus group interviews were conducted, comprised of two groups from each school, with an average of seven participants in each group.

Students considered caring and friendliness (91.0%), being a buddy (88.5%), and entertaining/humor (86.8%) as the top three characteristics of influential peers. The interviews revealed that the students believed that they are influential because of their cheerfulness and humor, considerateness, ability to communicate, popularity and sociability, sincerity and trustworthiness, and because they possess the characteristics of a leader. They also believed that their power to influence came about through their helpfulness, accommodation, and the closeness of their relationships. Their influence was manifested in both positive and negative ways on the academic pursuits and health-risk behaviors of their peers. In order to engage at-risk students in health promotion programs, it is important to identify their influential peers, and to understand how adolescent friends may help one another to resist behaviors that pose a risk to their health.