She painted and wrote poetry in high school, and studied the art of children's stories under the Japanese novelist and poet Sakae Tsuboi.

[2] Introduced by Ineko Sata, she studied literature from writer Sakae Tsuboi and oil painting from Western-style painter Yoshio Mori.

Around that time, Minami met her future husband, the mezzotint artist Yōzō Hamaguchi at Mori's studio.

[6][7][2] She became a member of the Free Artist Association in 1955, and in 1956 her work Fūkei (風景, Landscape) was purchased by the French Ministry of Education.

[2] In 1957, Hitsujikai no shōjo (羊飼いの少女, Shepherdess with Her Flock) was selected to be on the Christmas card from the Museum of Modern Art in New York, and in 1958, Heiwa no ki (平和の木, Tree of Peace) was reprinted on the greeting card of UNICEF, and Minami was named Official Artist of the United Nations in 1959.

[8] Shuntarō Tanikawa’s poetry collection Utsumuku Seinen (うつむく青年, Depressed Youth), published in 1970, included Minami's illustrations and cover design.

In 1998, Musée Hamaguchi Yōzō/Yamasa Collection (ミュゼ浜口陽三·ヤマサコレクション) was opened in Nihonbashi Kakigara-chō, Tokyo, and Minami's works are also on permanent display.