Kunihiro is traditionally transmitted as the eldest son of Kunimitsu, the celebrated smith active in . Old sword texts record that Kunihiro later adopted the name Kunimitsu, signing works in his father's name, and it is thought that he produced substitute works and signed in another's name ( and ) on his father's behalf. Among extant works bearing dates, examples from Bunpo 2 (1318) and Genko 4 (1324) are known, the latter also bearing an inscription stating "resident of ." Apart from these, most works are signed with only two characters, and no other dated examples survive. That Kunihiro was the son of Kunimitsu is considered correct both on stylistic grounds and in terms of chronology.
Kunihiro successfully inherited the style of his teacher and father Kunimitsu, excelling in the production of well-constructed and in tempering . His forging characteristically shows or mixed with , with well-adhering and ; frequently appears. The is typically a narrow with thick , in which fine and run along the , and the tends toward tightness and is bright and clear. While the workmanship in both and is closely comparable to Kunimitsu, traditional sources note that Kunihiro's turnback tends to be longer than that seen in his father's work, offering one distinguishing criterion for attribution.
Kunihiro's works tend toward a somewhat larger scale than those of Kunimitsu, with many examples showing slightly wider and proportions, though no are attributed to him. His output consists exclusively of in form with , and the character "" in his signature closely resembles that of Kunimitsu. Kunihiro's place within the lineage is that of a faithful inheritor who preserved the essential character of his father's art while exhibiting his own distinctive tendencies in construction and finish.