The aim of this study was to estimate the influence of counselor skills during brief motivational interventions (BMIs) on patient alcohol use 12 months later. Ninety-five BMIs delivered by five counselors of similar background and training were recorded and coded using the Motivational Interviewing Skills Code (MISC). Baseline alcohol measures and sociodemographics of patients did not differ across counselors, whereas MISC scores and outcome at 12 months did. Multilevel models showed that counselors with better motivational interviewing (MI) skills achieved better outcomes overall and maintained efficacy across all levels of an important predictor (patient ability to change), whereas counselors with poorer MI skills were effective mostly at high levels of ability to change. Findings indicated that avoidance of MI-inconsistent skills was more important than frequency of using MI-consistent skills and that training and selection of counselors should be based more on the overall MI-consistent gestalt than on particular MI techniques.