This study develops a model of emergent strategy formation at a large telecommunications firm. It integrates prominent traditions in strategy process research—strategy as patterned action, as iterated resource allocation and as practice—to show how emergent strategy originates as a project through autonomous strategic behavior, then subsequently becomes realized as a consequence of mobilizing wider support to provide impetus, manipulating strategic context to legitimate the project by constructing it as consonant with the prevailing concept of strategy, and altering structural context to embed it within organizational units, routines, and objectives. The study theorizes the role of “practices of strategy articulation” in emergent strategy formation, and explains why some autonomous strategic behavior becomes “ephemeral” and disappears rather than enduring to become emergent strategy. Copyright © 2013 John Wiley & Sons, Ltd.