Guido Viaro was born on September 9, 1897 in Badia Polesine, Veneto, Italy. The son of John Baptist Viaro and Santina Solda Viaro. His parents were farmers. Viaro's artistic talent was noticed at an early age by his uncle, Angelo Viaro, a sculptor of a great name in Bologna, Italy.
Guido Viaro attended the primary and junior high school in Badia Polesine Province of Sargo in Veneto, Italy. At the age of nine, he began his studies of painting in his homeland at a night art school, at the same time with his primary education.
In 1921, he recieved his Master of Drawing. Between 1921 and 1927 he studied painting in Venice and Bologna, Italy.
Guido Viaro traveled to Europe between 1921 and 1927.
In 1927 he moved to Brazil where he worked as an illustrator and caricaturist in São Paulo. His intention was not to stay in Brazil, but to know the country, living of his art. Two years later, he moved to Curitiba, where he came into contact with Theodore de Bonn and Alfredo Andersen, and illustrated the magazine "Joaquim" with his colleague Poty Lazzarotto in 1946, in addition to teaching.
Viaro was a professor of the School of Music and Fine Arts of Paraná (EMBAP), since 1948, the year of its foundation. As an art teacher in public schools in Curitiba, he noticed the spontaneous, authentic and expressive form of his students' drawings and paintings and decided to create a space for the exercise and development of art. Viaro dedicated more than 40 years of his life stimulating generations of painters who compose the current scenario.
Guido Viaro died in 1971 in Curitiba, Brazil.
Guido Viaro met Yolanda Stroppa, with whom he married in 1935.
