Vitamin E, consisting of tocopherols and tocotrienols, serves as a lipid-soluble antioxidant in sweet c kels, providing nutrients to both plants and humans. Though the key genes involved in the vitamin E biosynthesis pathway have been identified in plants, the genetic architecture of vitamin E content in sweet c kels remains largely unclear. In the present study, an association panel of 204 inbred lines of sweet c was constructed. Seven compounds of vitamin E were quantified in sweet c kels at 28 days after pollination. A total of 119 loci for vitamin E were identified using a genome-wide association study based on genotyping by sequencing, and a genetic network of vitamin E was constructed. Candidate genes identified were involved mainly in RNA regulation and protein metabolism. The known gene ZmVTE4, encoding γ-tocopherol methyltransferase, was significantly associated with four traits (α-tocopherol,α-tocotrienol, theα/γ-tocopherol ratio, and theα/γ-tocotrienol ratio). The effects of two causative markers on ZmVTE4 were validated by haplotype analysis. Finally, two elite cultivars (Yuetian 9 and Yuetian 22) with a 4.5-fold increase in the sum ofα-andγ-tocopherols were developed by marker-assisted selection, demonstrating the successful biofortification of sweet c. Three genes (DAHPS, ADT2, and cmu2) involved in chorismate and tyrosine synthesis were significantly associated with the α/γ-tocotrienol ratio. These results shed light on the genetic architecture of vitamin E and may accelerate the nutritional improvement of sweet c.