Sukemitsu held the court title Sakon-no-shōgen and signed in full beneath the school's single character : no Yoshioka-jū Sakon-no-shōgen Ki-no-Sukemitsu. He is the leading smith of the Yoshioka , the branch that, as the published sources put it, prospered from the end of into the period second only to the Fukuoka . The school takes its name from the character cut at the head of the tang, and its representative hands all share the element, Sukemitsu named first among Sukeyoshi, Sukeshige, Suketsugu and Sukeyoshi. His dated works run through Einin, Gen'ō, Genkō, Karyaku and Gentoku, a span of roughly the last decades, and several survive with the long signature still legible.
His hand has two faces, and the published sources are careful to keep them apart. The fundamental Yoshioka manner is the calmer, smaller-scale temper. On the long-signed the is an mixed with in which the stands, and over it he sets a -toned line into which and are intermingled, adhering, the running straight to a finish. The judges read one such blade as displaying the fundamental Yoshioka workmanship, 「吉岡本来の出来を示したもの」, the -toned edge with its small and the work that, in their words, clearly demonstrates the Yoshioka style. This is the register that distinguishes him from his parent school: not the towering clove-flower of Fukuoka but a quieter, more closely worked line.
The is the constant across his work. A well-forged , at times tightening into and mixed with , carries , frequent on the finest pieces, and a clear that the published sources note standing out on signed and attributed blades alike. On one the reflection begins low as a straight along the and breaks into a above, the Yoshioka he shares with the school. The is bright and clear, the temper carried in and rather than in great clusters, and a is commonly carved through. The published commentary calls one signed sound in both and and valuable for its inscription, 「地刃共に健全で出来がよく、銘は好資料」.
The other and rarer face is the high, flamboyant . The judges record that some of his blades retain comparatively showy features that, at a glance, can be mistaken for the Fukuoka with their large-pattern , 「一見福岡一文字派に紛れるような大模様の丁子」, even as they hold that his typical work is the more modest line, 「乱れの中に互の目が目立ち、やや小出来となるもの」, in which stands out within the . The , shortened and unsigned but gold-inlaid to him by the Honami house, shows this brilliant face: a dense with a standing and a mixed with , the published sources calling its workmanship 「華麗な丁子の出来が頗る見事」. The -attributed goes further still, an mixed with , very fine and thickly applied with abundant , over which the mixes and into a flamboyant pattern with fine , and , the narrowing toward the .
What sets Sukemitsu apart within his own lineage is exactly this division the judges draw, and the way both faces rest on the Yoshioka . He is held apart from Fukuoka by scale rather than by kind: his bright and his small, -marked are the Yoshioka norm, and only rarely does he reach back toward the large-pattern manner of the parent house. On the the published sources weigh the workmanship of and and judge the old attribution persuasive, appraising the blade a superior work of Yoshioka , 「吉岡一文字の上作」, the refined and meticulous forging especially noted. His dated and signed anchor that standard for the school, the fixed points against which the attributions are measured.
Sukemitsu's record reaches the highest ranks of the designation system. A signed dated Gen'ō 2 (1320), surviving and transmitted through the Maeda house of , is a National Treasure, and his work is further held among the Important Cultural Properties, including a Genkō-era signed and the polished by Honami Kōtoku. Five blades carry the rank, among them the brilliant with its mid- gold mounting bearing crests, and several preserve old provenance, with the Tokugawa Art Museum among the institutions holding his work and names such as Tokugawa Iemitsu, Abe Tadaaki and the Maeda family in the recorded chains. The National Treasure and the Important Cultural Properties are heritage held in trust, not blades a collector encounters; the designated pieces are few, and of recorded whereabouts most are long held rather than traded. A signed Yoshioka Sukemitsu coming to light is a landmark when it happens, a document of how the Yoshioka kept the manner alive into the close of the age.