He was the eldest son of Toyoakira YAMAUCHI (the 12th lord of the domain, and the younger brother of Toyosuke YAMAUCHI), the family head of the Southern house of the Yamauchi clan, which consist of the brothers and sisters of nobles of the Tosa Domain.
土佐藩連枝の山内南家当主・山内豊著（12代藩主・山内豊資の弟）の長男。