Following his father, Mitsuyuki became a retainer of the Kamakura Shogunate as the head of the Toki clan, but he also had a deep relationship with the Imperial Court as he lived in Kyoto and served as Saimen no bushi (the Imperial Palace Guard for the west side) for Emperor Gotoba.
父に続き土岐氏の惣領として鎌倉幕府の御家人に列したが在京し後鳥羽天皇の西面武士をも務めるなど朝廷との繋がりも深かった。