Grain boundary (GB) migration and grain growth in nanocrystalline metals are major obstructions to exploit these materials to their fullest potential, thus limiting their utility as advanced structural materials. Here, we investigate the effect of Zr segregation to a Ni GB on migration and subsequent strengthening during shear deformation and high-temperature bending creep. Specifically, using molecular dynamics simulation, we simulate deformation of a Ni bicrystal specimen having a symmetric n-ary sumation 5 grain boundary with and without segregated Zr. It is found that GB segregation up to 0.4 at.% pins the CSL boundary resulting in increased shear strength. Similar behavior is also observed in the case of bending creep deformation where the creep resistance increases only up to 0.4 at.%. This study indicates that larger amounts of GB segregation cause destabilization of the local atomic structure and consequently affect the GB stiffness. Moreover, we investigate the effect of Zr segregation on the interaction between the GB and a dislocation. We find that the preexisting dislocation is absorbed in the GB region for both clean and segregated specimens; however, the absorption path of the dislocation is different due to the change in GB stiffness caused by the Zr segregation.