This paper concentrates on vibration suppression and transient stability in the key yet understudied field of a newly variable-structure journal bearing that actively adjusts the offset coefficient and elliptical ratio. A novel tribo-dynamic model and modified stability criterion are proposed and validated to investigate the nonlinear characteristics of adjustable offset-elliptical journal bearings (AOEJBs), especially under time-varying loads and bi-directional misalignment. Moreover, bearing behaviors are comparatively analyzed considering multiple coupling factors. The evolution mechanism of load change, varying lubricants, and misalignment variation on the transient stability is studied. The results demonstrate satisfactory vibration suppression and transient performance of AOEJBs, providing a valuable reference for the lubrication design of dynamically loaded bearings.