Sukemitsu is a name borne across multiple generations of the school in Province, with reference works listing as many as seven smiths of the name. The first generation is identified by dated works from the Eikyō era (1429–1441), while the most prominent figure in the lineage — the third-generation Sukemitsu — styled himself Rokurōzaemon no Jō and was active from the Eikyō era through the Bunmei era (1469–1487). A by his second son Sakyō no Jō Munemitsu, dated Bunmei 9, bears the inscription " Sukemitsu's second son," establishing that Sukemitsu was the father of both Ukyō no Katsumitsu and Sakyō no Jō Munemitsu — two of the most celebrated names in late sword-making. The further notes that many smiths of this period "moved about and forged in various locales," and indeed a dated Hōtoku 3 (1451) bears the inscription "Made at Takehara in Settsu Province," providing valuable evidence of itinerant production. Separately, a Yamato smith also signed Sukemitsu (助光, using distinct kanji) is recorded in the Senjuin lineage with works dated to the Shōan era (1299–1302) of the late period; extant signed works by this Yamato Sukemitsu are described as "extremely few" and "extremely rare."
The Sukemitsu lineage works primarily in the Ōei- manner, producing a characteristic — "opened at the waist" — mixed with , -ba, and angular elements. The is consistently described as bright, with adhering and fine and running throughout. The forging is typically mixed with , and appears prominently. Early-generation works display a "calm " that "clearly expresses Sukemitsu's characteristic workmanship," while later pieces show the amplitude of the diminishing and the becoming less pronounced — features the identifies as indicating "a somewhat later period" in the transition from Ōei- into . The Yamato Sukemitsu, by contrast, favors a basis mixed with and , with entering well and the described as "clear and bright." His signature is distinctive: a bold, large two-character cut with a thick chisel, always positioned above the — "entirely different from that of Yoshioka Sukemitsu."
The Sukemitsu lineage occupies a pivotal position in the tradition, standing at the generational bridge between the grandeur of Ōei- and the pragmatism of . The recognizes works by this lineage as demonstrating "the high level of his technique" and, given their rarity, as possessing "high value as source material for study." One is praised for retaining "abundant " in condition, judged "an excellent piece" among the smith's "comparatively few extant works." The Yamato Sukemitsu, though far more obscure, commands particular scholarly interest because his works display "two different modes of workmanship" — one distinctly Yamato, the other showing "a distinctly -like temperament" — leading the to conclude that "the relationship between Sukemitsu and smiths should be further examined in future." Both lines are unified by the exceptional scarcity of their surviving oeuvre and by the institutional judgment that their best works are of fine quality and sound preservation.