This study explores the impetus for and impact of four urban teachers' extracurricular investments. Framing teacher investment as work voluntarily undertaken with an eye toward bringing about a highly desired, yet highly uncertain, end, we argue that the outcome of these often-hidden investments have identity and career implications for teachers. Through a comparison of two case studies in the southeast and northeast United States, we investigate why and how teachers come to invest themselves in particular extracurricular projects, the identity implications of the investments, and how the ultimate outcome of the investments may influence their decision to stay in or leave the profession. Findings reveal that teachers' extracurricular investments--either in individual students or whole-school projects--are intimately tied to their identities and career trajectories. Implications are offered for research, teacher education, and policy.