This dissertation explores frontline nurses' perceptions of peer support in fostering emotional, professional, and organizational support and commitment in different contexts. This study draws together scholarship on street-level bureaucrats (SLBs) and formal and informal training in nursing to build on research demonstrating that internal organizational elements such as formal training and informal peer interaction continuously develop SLBs' professional and organizational personalities. Also, research traditions on SLBs regard peer interaction as policy implementation using "service styles" to build stronger ties with peers to solve problems and better respond to the needs of citizens and communities. Despite the prominent role peers play in scholarly research on SLBs, few empirical studies have contextualized the meaning of peer support in different settings to examine how it affects professional meaning and organizational commitment in a specific industry. This dissertation expands on the findings of several studies that demonstrate that peer relatedness is an important component of frontline work. The distinctive contribution of this dissertation is using narrative analysis to collect and analyze stories of firsthand experiences told by personal narratives from mental health, military, and emergency nurses in public hospitals to thoroughly compare the perception of informal or formal peer support influence and highlight its evaluative aspects across different settings. This dissertation contributes to the street-level bureaucracy theory by providing empirical evidence in contextualizing peer support as a catalyst for emotional support and a buffer for organizational uncertainty in various emotionally charged healthcare settings. / Doctor of Philosophy / This dissertation focuses on the narratives of frontline nurses in mental health, military, and emergency settings to highlight the impact of peer support on nurses' emotional well-being, as well as professional development, fulfillment, and commitment in diverse healthcare environments. This study illuminates how formal (preceptorship) and informal (mentorship) training or peer support shape nurses' professional identities, engagement, and commitment. Despite the acknowledged importance of peer support in public administration scholarly discourse, few studies have explored its nuanced significance across different healthcare settings. This dissertation addresses this gap by employing narrative analysis to examine narratives from mental health, military, and emergency nurses in public hospitals. By comparing informal and formal peer support perceptions of these different types of nurses, this study explores the realities of frontline healthcare delivery, including the emotional toll and systemic challenges they face, personal development lessons learned, and dynamics surrounding co-supporting quality care through peer support. Subsequently, this study highlights the critical role of peer support in developing and enhancing the psychological drivers — autonomy, mastery, purposefulness — and social drivers — supportive workplace, sense of belonging, and psychological safety— of nurses, thereby fostering a supportive environment and enhancing their competency and the quality and safety of patient care.