Purpose: The purpose of this paper is to explore the tensions between external accountability obligations, educator's professional values, and student needs. Strategic, cognitive, and moral dimensions of this tension are captured with the central category of integrity. Design/methodology/approach: This is a mixed methods study that compares five exceptionally high performing middle schools with four exceptionally low performing middle schools in the state of California (USA), controlling for demographics, school context factors, and below average performance range. Findings: It is found that schools under similar circumstances differ on the degree of integrity. Schools with high integrity have a good balance between values and reality, are more cohesive and more open to dissent. In each case, integrity was associated with an expansion of agency that combined moral earnestness with prudent strategizing and actively constructing interpretive frames that maintained a school's sense of self-worth. Integrity develops or survives with a good dose of educational leaders' personal strength, but also depends on leaders' insistence to fully exhaust the moral horizon of an institution which obligates educators to balance equity, system efficiency, child-centeredness and professionalism with prudence. Research limitations/implications: This is a case study of nine schools in one state. Explanatory relationships can be explored, but not generalized. Practical implications: The research has implications for leadership. It demonstrates the power of integrity as a key virtue of leadership under accountability pressures. It shows the different ways integrity can be forged in schools and the different ways it can be missed with consequences for school life. Social implications: The paper stresses the point that it is quite conceivable that ideological zeal, Machiavellian strategizing, or eager system conformism may produce more forceful agency than integrity. But as everyday responses they are not as realistic, ethical or productive as the striving for integrity. Originality/value: The practitioner literature often points to integrity as a desirable quality when dealing with tensions of the sort addressed in this paper, but little systematic theoretical thinking and empirical exploration of this concept exists. The paper makes an advance in both areas. (Contains 9 tables, 3 figures and 7 notes.)