Excessive oxidation of protein and lipids in pork leads to quality degradation and loss of nutrients. Kappa‐selenocarrageenan (Se‐K) can not only be used as a selenium enhancer but also as an antioxidant. To explore potential antioxidants that could be applied to pork, the effect of Se‐K on myofibrillar protein (MP) and lipid oxidation was investigated. The results demonstrated that Se‐K could scavenge hydroxyl radicals, DPPH radicals, and ABTS radicals. It was found that Se‐K inhibited the formation of carbonyls and decreased the loss of sulfhydryl groups of MP. Se‐K also inhibited cross‐linking, aggregation, unfolding, and structural transformation of MP and repressed the increase in surface hydrophobicity. Additionally, Se‐K enhanced the emulsibility, textural properties, and water‐holding capacity of MP. We also found that Se‐K delayed the increase in acid value, peroxide value, and thiobarbituric acid reactive substances value. Furthermore, Se‐K inhibited the degradation of unsaturated fatty acids, especially linoleic acid. Overall, Se‐K was effective in inhibiting MP and lipid oxidation and could be a potential antioxidant for pork.