The Community Earth System Model (CESM) is a fully-coupled global climate model, and is maintained by the National Center for Atmospheric Research (NCAR). Composed of several separate models simultaneously simulating the earth's atmosphere, ocean, land surface, sea-ice, land-ice, river transport and wave, and one central coupler component, the CESM allows researchers to conduct fundamental research into the earth's past, present and future climate states. CESM1 contains totally new infrastructure capabilities, the implementation of a coupling architecture, and model parameterization development. These permit new flexibility and extensibility to address the challenges involved in earth system modeling with ultra high resolution simulations on High Performance Computing (HPC) platforms using tens-of-thousands of cores. Firstly, the infrastructure of the model is introduced, and also the notable improvements. The CESM1 coupling architecture provides “plug and play” capability of data and active components and includes a user-friendly scripting system and informative timing utilities. Then, the processor (PE) layout is customized for the load balancing on high-performance computers to optimize the throughput or efficiency of a CESM experiment. At the end of the paper, the port validation and model verification are made for the ocean model—the Parallel Ocean Program version 2 (POP2) which has properly ported to the machine—Polaris at Ocean University of China. The POP2 model output is subsequently verified to be a successful port, and CESM1 POP2 ocean-model solutions are the same as solutions generated on a trusted machine—bluefire at NCAR. Together, it enables a user to create a wide variety of "out-of-the-box" experiments for different model configurations and resolutions and also to determine the optimal load balance for those experiments to ensure maximal throughput and efficiency. The results and experiments will provide useful experience and method to the new CESM users to make simulations and load balancing of the model.