Emotional intelligence (EI) has developed as a significant construct with an impact on human performance, interpersonal relations, persistence in academic and workplace performance, and so on. This review provides an integration of the development, conceptualizations, and empirical applications of EI and shows its applicability across various psychological, educational, and organizational settings. The paper provides a prose overview of the key models of EI (ability, mixed and trait) with different views on emotional functioning and measured by different instruments (MCSET, EQ-i and TEIQue, respectively). Central to these models is the Four-Branch Model of Mayer and Salovey which depicts EI as comprising a set of hierarchically inter-related competencies that include the perception of emotion, the use of emotion, the understanding of emotion and the management of emotion. The literature suggests that EI improves engagement of students, stress coping, conflict management and adaptability of leadership especially in times of uncertainty and high emotional pressure. However, problems persist because of definitional inconsistencies, overlapping constructs with personality and cognition, and problems of measurement reliability and cross-cultural validity. The theoretical underpinnings of EI - based on social intelligence, multiple intelligences, self-management, and social cognitive theory - is a strong foundation and also an invitation for fine-tuning. This paper advocates for more integrative, longitudinal and culturally sensitive methods to enhance EI research, specifically in emerging contexts, such as digital education, virtual workplaces and global leadership. Ultimately, training and educating for EI holds promise for resilience, ethical leadership, academic excellence and organization performance in an ever-changing world.