These formative years of practicing Western and traditional Japanese mediums gave a dual foundation to his future work. He dedicated himself to painting and moved to Paris in 1952, enrolling at the Académie de la grand chaumière, being one of the first generation of the post-war Japanese artists to join the international avant-garde art scene.

Sugai was immediately noticed in Paris for his delicate touch and use of abstract gestures resembling primitive forms. He had his first solo show at Galerie Craven in 1954. In 1955 he made his first work in edition (Diable Rouge, a lithograph) and decided that from now on print work (lithographs, etchings and later silkscreens) was going to be an important part of his oeuvre. One of the reasons was to make his work more accessible. Between 1955 and 1996 Sugaï produced a little under 400 works in edition.

Considered part of the École de Paris (School of Paris) and the Nouveau Réalisme (New Realism) movements, in 1962 he began to move from calligraphic, mainly monochromatic, organic motifs to more hard-edge geometric forms painted with clear colors. This aesthetic was more often than not influenced by speeding the curves of the freeways surrounding Paris in his beloved Porsche. He was possessed with speed and in a lot of his work we find abstracted roads (The S shape) details of roadsigns, parkings and in general an abstract visual language inspired by what he would see through his window moving at great speed. City and rural Landscapes transformed into simple colored compositions. 

Sugaï found great joy in the act of repetition and some iconic shapes have been appearing in his work throughout his whole career, first loosely and soft in his early etchings, paintings and lithographs, later hard edged and straight in his silkscreens.

His artworks were shown in numerous exhibitions around the world and most of his paintings are in the collections of well-known museums (Such as MOMA and Centre Pompidou) and important collectors.

Sugai died in Kobe in 1996.