The three articles that comprise this dissertation examine different ways that current teachers can express leadership outside of their classrooms, through labor activity and within-school instructional leadership. I use descriptive and quasi-experimental quantitative analysis to examine which teachers take on these roles, their effectiveness, the effects of leadership programs, and the aftermath of teacher activism. In 2018, a wave of educator strikes called Red for Ed swept through several states. Educators in Arizona won additional funding from the state legislature, supposedly for teacher salaries, which school boards could spend as they saw fit. This paper quantitatively examines the participation and results of the 2018 Arizona educator strike, using this example to speak to theoretical work on types of union activity. I find that after the strike, per-pupil funding, teacher salaries, and student support staff salaries all increased. However, post-strike funding was added to Arizona's pre-existing funding formula, which already advantaged the small, rural, predominantly White districts whose educators were less likely to go on strike. Educators who went on strike thus received less money for their districts and smaller raises than non-participating educators, showing that despite its gains, Red for Ed was unable to challenge deeper structures in Arizona education. Teacher coaching programs have shown promising effects on student achievement, but these effects vary substantially across programs and context and seem susceptible to problems of scale. Additionally, the effect of coaching on teacher retention are not known. In this paper, we evaluate Teacher Leadership and Collaboration (TLC), a large-scale program in which current teachers are released from the classroom part-time in order to coach and evaluate other teachers. TLC was rolled out across a single urban district in five cohorts of schools and eventually reached over 1,000 teacher-coaches and over 6,000 mentee teachers, presenting a unique opportunity to study the effect of large-scale coaching on teachers and students. We use a difference-in-differences approach with modified estimators to account for the staggered roll-out to estimate the effects of TLC implementation on a school's average teacher retention and student achievement. With a minimum detectable effect of 5 percentage points in teacher retention and 0.05 standard deviations in test scores, we find no effect of TLC on teacher retention or student test scores. Teacher coaching has the potential to improve instructional quality and student learning, but there are concerns about developing and maintaining enough high-quality coaches to take coaching programs to scale. In this paper we take up the issue of coach quality in a large-scale teacher coaching program (over 1,000 coaches supporting over 6,000 teachers) that releases current teachers from half their time in the classroom to coach newer or struggling teachers. We examine the properties, assumptions, correlations, and predictors of five measures of instructional coach quality, in order to explore the coach quality issue that is crucial to scaling instructional coaching. We consider three professional ratings of coaches, including assessments from school leaders, mentee teachers, and self-assessments from the coaches themselves. Additionally, we construct measures of a coach's value-added to their mentee teachers' observation scores and those teachers' students' test scores. We find correlations within professional ratings from different members of the school community, and correlations between value-added to teachers' observations and to teachers' students' ELA test scores. However, there are no statistically significant positive correlations connecting these professional ratings to value-added, reflecting both the imprecision of value-added and the possibility that improving teachers' instruction may be a different domain of coaching than building relationships and assisting the school as a whole. Additionally, we find that more effective teachers who become coaches tend to be more highly rated by their school leaders and mentee teachers, but do not necessarily have higher value-added. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]