This article examines teacher leader role development and definition by looking at one emergent model of distributed leadership: the hybrid teacher leader (HTL). HTLs are teachers whose official schedule includes both teaching K-12 students and leading teachers in some capacity. Participants included six HTLs across four school districts over 2 years, as well as their administrators. Extensive qualitative data were collected and subsequently analyzed, including interviews, on-site observations, and artifacts. Findings included a pervasive lack of role definition for the HTLs amid heightened organizational complexity, leading to numerous de facto definitions emerging. Conflicting de facto definitions led to diminished success for the HTLs, relationship deterioration, a reversion to professional development removed from the classroom, and a lack of capacity to account for HTL efficacy. The study concludes that for new teacher leaders to be successful, states and districts will need to much more clearly define roles and priorities and be specific about how budget-compensated teacher leader time is used. (Contains 1 table and 1 figure.)