Yuli Vilyumainis was born in Latvia on April 25, 1909.
He studied art at the Riga City School of Crafts during the evening from 1925 to 1926. He graduated from the landscape studio of the Latvian Art academy in 1935.
He participated in many exhibitions of the society, "Zaļā zeme", since 1935, the Society of Mukusala Artists since 1935, the Culture Foundation in 1935/36 and 1937/38 and numerous All–Union exhibitions.
He had solo exhibitions in Riga (1942, 1973, 1984) and Jurmala (1977).
Vilyumainis became a Laureate of the Culture Foundation in 1944. In 1979, he became an Honored Artist of Latvia.
He became a member of the Latvian Artists' Union in 1946.
He worked as one of L. Libert's and P. Rozlapa's stage designers for the Latvian National Opera from 1935 to 1937. He was a professor of drawing in Rezekne from 1937 to 1938 and in Riga from 1938 to 1944. He was the Director of the Kuldiga School of Applied Arts in 1945 as well as a professor at the Riga School of Applied Arts (1945 – 46, 1949 – 53) and the Janis Rozentals Riga School of Art (1953 – 69). He, also, was the Director of the Latvian Art Academy (1946 – 47). He worked in the artist cooperative, "Māksla" (1953 - 69).
His works are found in private collections and museums in Russia, Japan, Austria, Switzerland, USA, Germany, Czech, Poland, France, Sweden, Estonia, Lithuania etc.
Vilyumainis died on August 15, 1981.
He is listed in Matthew Bown′s, A Dictionary of Twentieth Century Russian and Soviet Painters.