Later, when Nobunaga started the Conquest of Shikoku, Hideyoshi was going to strengthen his clout in Shikoku, thus Hidetsugu was sent to become the adopted child of Yasunaga MIYOSHI who had strong power in Awa Province at the time, where he was given the name Nobuyoshi MIYOSHI.
その後、信長が開始した四国征伐において、秀吉が四国に対する影響力を強めるため、当時阿波国で勢力を誇っていた三好康長に養子として送り込まれ、三好信吉と名乗る。