Leading an accounting firm, an advertising agency, a consultancy, an investment bank, or a law firm is not about giving orders to employees further down the hierarchy. It's about manoeuvring a group of peers who are star performers—who constantly question, debate, and even oppose initiatives. It's like boxing with one hand tied behind your back: You lack the power to enforce decisions—even though you are in charge. This article, by two Bain partners, examines how leaders of professional service firms successfully meet that challenge. It lays out how they can become masters at brokering agreement on important decisions among the firm's elite players—a delicate balancing act that requires emotional intelligence, constant monitoring of the firm's undercurrents, careful groundwork preparation for strategic moves, and continual tweaking of organisational structures to make sure they serve the needs of both the firm and its star players.