Libraries play a crucial role in promoting information access and intellectual growth. To ensure library personnel thrive and meet diverse client needs, it is essential to understand their professional development and performance. There is insufficient research in a library working environment that integrates training and development, work performance, and social capital among personnel into a unified paradigm. This study is being carried out in this context to assess all three variables from library personnel and the findings will serve as a basis for improving training and development programs, enhancing work performance, and fostering social capital among library personnel, thus leading to informed decision-making processes related to human resource development and organizational strategy for optimizing library personnel performance and promoting a conducive working environment. The study utilized descriptive quantitative methodology, collecting data through a structured survey questionnaire from the South Manila Educational Consortium Libraries. Sixty-one (61) questionnaires were completed and returned from the total population, and SPSS was used for analysis, interpretation, frequency distribution, percentages, and mean. The findings showed that seminars, conferences, and workshops were the most available and widely used interventions of the respondents. The study also found that inadequate funding hinders training and development, with library funding being a key strategy to enhance them. Furthermore, respondents demonstrated above-average task and contextual performance, excellent counterproductive work behavior, and high levels of structural, relational, and cognitive social capital. Based on the notable results, it becomes evident that the training and development interventions of respondents were not significantly available. Additionally, it was observed that most of the library personnel made full use of the available interventions. Also, the study discovered positive work performance and the presence of social capital in the examined population. Keywords: Academic Library, Training and Development, Work Performance, Social Capital, Library Personnel