This study investigates the determinants of effective manpower operations in Nigerian building construction firms within the Volatility, Uncertainty, Complexity, and Ambiguity (VUCA) framework. A quantitative research design was adopted, using a structured questionnaire administered to construction professionals, including architects, builders, civil engineers, and quantity surveyors. Data were analyzed using descriptive statistics and principal component analysis with varimax rotation. Ten primary factors influencing manpower effectiveness were identified, with supervision ranking highest, followed by occupational education and training, site management, and camping conditions. Four principal components emerged: firm reputation and workforce development; material management and supervision; workforce welfare and operational flow; and physical site environment, together accounting for 57.142% of the total variance. The findings underscore the significance of leadership, workforce development, welfare provisions, and resource coordination in enhancing labor productivity and operational efficiency. The study further reveals a dynamic relationship between productivity demands and WB under VUCA conditions. These results indicate the need for construction firms to adopt IMMS that emphasize training, effective supervision, welfare improvement, and enhanced site conditions. This research advances human capital theory by demonstrating that organizational, operational, and environmental factors influence manpower effectiveness and affirms the relevance of the VUCA framework in examining workforce dynamics in the Nigerian construction sector.