After returning to Korea before liberation and developing his early quasi-abstract ink painting style, Lee Ungno relocated to France in 1958, where he fully established his standing as an abstract artist.
Lee was taught classical Chinese (한문, 漢文) by his father, and enrolled in Hongseong Botong Hakyo (홍성보통학교, 홍성초등학교, 洪城普通學校) for his primary education, but soon dropped out due to his family's financial situation.
[19] Toward the end of the Pacific War, Lee Ungno sold his newspaper shop in Tokyo and returned to Seoul in March 1945, then moved to Yesan to avoid conscription.
[22] From 1948 to 1950, he taught in the Oriental Painting Department of Hongik University, while continuously exhibiting in Seoul, Jeonju (전주, 全州), and Daejeon (대전, 大田) up to the outbreak of the Korean War.
[23][24] By this time, Lee was gradually transitioning to abstraction, using "acts of conscious deformation" to grid "pictorial space using perpendicular lines that are successively layered onto each other to both produce the illusion of spatial recession and reinforce the flatness of the physical support.
[26] When the Korean War broke out in 1950, Lee Ungno moved to Yesan with his family, along with Park In-gyeong, but continued to hold various exhibitions and trained students.
Lee returned to Seoul after ceasefire in July 1953 and held a solo exhibition where he showcased many of his new paintings that depicted scenes from rural life, such as farmlands, markets, farm animals, and people seeking refuge from the war.
[36][37] In France, Lee was influenced by Art Informel and European abstract expressionism and became well-recognized for his unique modern painting techniques using traditional Eastern materials.
[38][39] In particular, he developed a novel style of collage using crumpled, cut, and pasted hwaseonji (화선지, 畵宣紙), thin sheets of paper used for calligraphy, and received wide acclaim in both Europe and Korea.
He held solo exhibitions in numerous galleries around Europe, including Musée des beaux-arts La Chaux-de-Fonds and Galerie Numaga, Switzerland, National museet Kobenhavn, Denmark, and Friedrich & Dahlem, Munich.
[57] While incarcerated, Lee continued to produce art using any materials he could find, such as soy sauce, wooden lunch boxes, toilet paper, ballpoint pens, and rice.
[58][59] In 1977, Lee Ungno's wife, Park In-gyeong, was involved in yet another political scandal where she was suspected of being an accomplice to the attempted kidnapping of South Korean pianist Kun-Woo Paik (백건우, 白建宇, 1946–present) and actress Yoon Jeong-hee (윤정희, 尹靜姬, 1944–2023) to North Korea in Zagreb.
[63][64] During his stay in France, Lee Ungno developed his unique collage and "arrachage" technique, where he would scrunch up, tear, arrange, and layer various types of paper and use several colours, mostly natural hues, to create multi-layered and freeflowing works.
나는 동양화와 한자, 한글의 선의 움직임에서 출발, 공간구성과 조화로 나의 화풍을 발전시켰다"[67]His abstract letter series developed from the 1960s, and Lee Ungno experimented with simplifying and evening out relief surfaces on the canvas and systemizing the rhythmic formations of colours, structures, and volume in his earlier experimentations.
His return to France from South Korea after his release from prison signalled a brief shift from the 'humorous' tones of his works to 'frugal' or 'cold' images, involving terse and rigid geometric forms.
[78][79] Though he lived far from his homeland, the Gwangju Uprising in 1980 greatly influenced the artist and caused him to choose formative elements over complete abstraction in as he thought that it would resonate with the general public.