Hierarchical structural models comprising the general factor solution have been established in different fields of psychology (e.g. general factor of intelligence). In the personality domain however, the discussion has been between two-, three-, five- or more factor solutions, while the general factor solution has never been taken seriously until a very recent time. In this study, the evidence for the general factor of personality (GFP) is presented and a new hierarchical structural model of personality is proposed. Additionally, the psychological nature of the GFP or the Big One is discussed as well as its possible evolutionary, genetic and neurophysiological basis.