Though he was born the son of Imperial Prince Tokiwainomiya Matahito and was given the title of Imperial Prince in 1381, this was accomplished behind-the-scenes because Prince Masahito offered one of his beloved concubines called Koshosho to Yoshimitsu ASHIKAGA and Yoshimitsu produced a child with her who would become the Imperial Prince.
常盤井宮全仁親王の子として生まれ、永徳元年（1381年）に親王宣下を受けるが、これは愛妾の一人である小少将なる女性を足利義満に差し出し、その結果、義満の根回しによって為された物だったという。