Folklore of the Aizu region says that Katsutoyo was part of the Yamauchi clan (a branch family of Sudo Ymanouchi clan), which worked for the Ashina clan, which in turn became Nobunaga's vassal when he wandered, but this doesn't fit Katsutoyo's accomplishments during the Owari period.
また会津地方では葦名氏に仕えた山内氏（首藤山内氏の庶流）の子が流浪して信長に仕えたのが一豊であるとする伝承もあるが、これは尾張時代の一豊の事績と合致しないために否定されている。