Display omitted •Bottom electrode has a strong influence on the growth of the active layer.•LaNiO3 electrode strongly stabilizes the perovskite phase.•Stabilization is mainly related to increased interface roughness.•Increased interface roughness does not have adverse effects on the film properties. Pulsed-laser deposition was used to prepare Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films on (LaNiO3)/SrTiO3 substrates. We found that the bottom electrode has an immense influence on the properties of the overgrown active layer. Specifically, we found that the use of LaNiO3 (LNO) as the electrode material strongly stabilizes the perovskite phase and significantly expands the process window for the preparation of phase-pure PMN-PT as compared to a direct deposition on SrTiO3 (STO) substrates. Based on our experiments, the stabilization is achieved primarily due to the increased interface roughness, which enhances the sticking of Pb-based species, thereby suppressing the formation of undesired Pb-deficient pyrochlore inclusions. The roughness of the interface does not have adverse effects on the quality of the films. In fact, the film prepared on the LNO/STO template from the Pb-rich target exhibited superior electrical properties as compared to the film prepared directly on STO. By understanding the mechanism, we were able to exploit it and prepare an STO/Nb:STO template with a rough surface, which strongly enhanced the stability of the perovskite phase. This approach can be used to design templates for different device configurations.