This Article offers a formal legal definition of “leadership” drawn from an unusual quarter: criminal sentencing. Sentencing guidelines that include adjustments based on the extent to which a defendant was a “leader” have spawned hundreds of appellate court cases attempting to develop a thoughtful, workable definition of the term. Reviewing these cases, this Article offers 25 separate characteristics courts have found material to a legal judgment as to whether an individual has been a leader within a criminal enterprise. Eleven of these characteristics can be organized into three categories, which operate on the boundaries of the leadership concept. The first category contains those circumstances courts have found do not, by themselves, con...