In the most challenging era in human history, the scientific community recognizes spirituality as a fundamental factor of human intelligence. Researchers from different fields such as Psychology, Medicine, Educational sciences, Economy and Business embrace the notion of Spiritual Intelligence. Nevertheless, it is considered as one of the most controversial and highly debated notions. The first section of this study gives a brief overview of the essential theoretical framework including definitions and theories related to Spiritual Intelligence. In the second section, we present a layered approach of Spiritual Intelligence based on the corresponding layered models of Knowledge-Intelligence-Consciousness. The results of this study showed that Spiritual Intelligence constitutes the backbone of every subsystem of human intelligence as it integrates, matures and transforms every physical, intellectual, and emotional ability and leads to the highest forms of self-awareness, self-knowledge and consciousness. The realization of our true Self, of our hidden and highest potentialities is tied inseparably with the hierarchical organization of knowledge through metacognition and executive functions. Specifically, higher order forms of self-observation, self-regulation through attentional, emotional and impulse control, problem solving, mental flexibility and adaptation could reveal our true and eternal identity. Spiritual intelligence is essential to be incorporated mainly into the dialogue of business ethics, leadership, mental health and psychotherapy, education especially in the case of learning disabilities and gifted education