Proteomic sequencing of postmortem human brain can identify dysfunctional proteins that contribute to neurodegenerative disorders like Alzheimer’s disease and frontotemporal dementia. Similar studies in chronic traumatic encephalopathy are limited, but may provide important new insights into this disorder. Given our previous success with identifying pathology associated proteins, we performed proteomic sequencing of detergent insoluble brain homogenates from frontal cortex of deceased subjects with CTE covering a range of CTE pathologic stages. We compared the insoluble proteome of CTE brain to control and AD brains to identify differentially expressed proteins. We identified over 4000 proteins in CTE brains, including significant enrichment of the microtubule associated protein tau. We also found enrichment and pathologic aggregation of RNA processing factors as seen previously in AD, supporting the previously recognized overlap between AD and CTE. In addition to these similarities, we identified CTE-specific enrichment of a number of proteins which increase with increasing severity of CTE pathology. NADPH dehydrogenase quinone 1 (NQO1) was one of the proteins which showed significant enrichment in CTE and also correlated with increasing CTE stage. NQO1 demonstrated neuropathologic correlation with hyperphosphorylated tau in glial cells, mainly astrocytes. These results demonstrate that quantitative proteomic sequencing of CTE postmortem human brain can identify disease relevant findings and novel cellular pathways involved in CTE pathogenesis.