Despite the link between school-lunch participation and student health, only half of adolescents with the program in their schools participate on a given day. A multi-pronged school lunch promotion intervention was implemented in middle and high schools in an urban, low-income school district to improve school lunch participation and reduce food waste. This dissertation assesses the impact of the intervention on student and teacher perceptions of school lunch and explores how leadership shaped intervention implementation. Using student survey data, paper 1 explores the theoretical pathways (perceptions of school-lunch quality and convenience) through which the intervention was expected to increase school-lunch participation and decrease plate waste. We observed modest changes in perceptions of school-lunch quality and no changes in perceptions of school-lunch convenience. Results suggest that additional efforts are needed to improve school-lunch participation and dietary intake. Paper 2 utilizes teacher survey data to assess the impact of the intervention on teacher perceptions, modeling, and encouragement related to school lunch. Results indicate that the intervention had a modest effect on teacher-reported frequency of eating in the cafeteria with students and on encouraging students to participate in the school-lunch program. There was no change, however, in teacher perceptions of or participation in the school-lunch program. The paper concludes that improvements in teacher perceptions of school meals may not be needed in order for teachers to promote the school-lunch program to students. Paper 3 focuses on the implementation of the intervention. Through qualitative interviews, the paper characterizes implementation leadership in the context of the intervention, and contextualizes emergent findings in the existing implementation science literature. Four major themes emerged reflecting the ways in which leaders are perceived to influence implementation effectiveness: (1) leader understanding of the technical and operational details of the intervention; (2) leader ability to develop and communicate intervention plans; (3) leader supervisory oversight over implementation staff and contractors; and (4) leader acknowledgment that 'innovation' requires time and stakeholder input--the absence of which can threaten cohesion and buy in. Implementation leadership functions in a school nutrition context appear similar to those identified in the implementation science literature. Results are the first to illustrate how these leadership dimensions are performed in a school nutrition setting. [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.]