Human colon cancer is the third leading cause of mortality in the United States and worldwide. Chemoprevention using diet is widely accepted as a promising approach for cancer management. Numerous population studies indicate a negative correlation between the incidence of colon cancer and consumption of whole grains with a high content of bioactive phenolic compounds. In the current study, we evaluated the anticancer properties of a high phenolic sorghum bran extract prepared using 70% ethanol with 5% citric acid solvent at room temperature. A significant dose-dependent suppression of cell proliferation was observed in human colon cancer cells treated with the high phenolic sorghum bran extract. Apoptosis and S phase growth arrest were induced, while cell migration and invasion were inhibited by this treatment; these effects were accompanied by altered expression of apoptosis, cell cycle, and metastasis-regulating genes. We also found that the high phenolic sorghum bran extract stimulated DNA damage in association with induction of extracellular signal-regulated kinase (ERK) and c-Jun-NH2-terminal kinase (JNK) and subsequent expression of activating transcription factor 3 (ATF3). The present study expands our understanding of the potential use of high phenolic sorghum bran to prevent human colon cancer.