The constant increase of turbomachinery rotational speed has brought the design and the use of journal bearings to their very limits: tilting pad journal bearings (TPJBs) have been introduced for high-speed/high-load applications due to their intrinsic stability properties and can be used both in transient and steady-state operations obtaining superior performances. An accurate analysis of the TPJBs behavior is essential for a successful design and operation of the system; however, it is necessary to reach a compromise between the accuracy of the results provided by the TPJB model and its computational cost. This research paper exposes the development of an innovative and efficient quasi-3D TPJB modeling approach that allows the simultaneous analysis of the system rotordynamics and the supply plant behavior; the majority of existing models describe these aspects separately but their complex interaction must be taken into account to obtain a more accurate characterization of the system. Furthermore, the proposed model is characterized by a high numerical efficiency and modularity, allowing for complex transient simulations of the complete plant and for the representation of different kind of bearings. The TPJB model has been developed and experimentally validated in collaboration with an industrial partner which provided the technical data of the system and the results of experimental tests.