A gas lift injection packer assembly, a gas lift injection system that includes the assembly, and methods utilizing the assembly and system are disclosed. The gas lift injection packer assembly includes a top sub, a packer coupled to the top sub, a bottom sub coupled to the packer, a sleeve disposed within the top sub, the packer, and the bottom sub. The inner diameters of the components of the gas lift injection packer assembly form a continuous passage from end-to-end of the gas lift injection packer assembly such that a downhole tool can be moved through the gas lift injection packer assembly while the gas lift injection packer assembly is sealed in a wellbore. A gas inlet port of the top sub can be formed such that an inner wall of the gas inlet port is the housing for a check valve.