As the daughter of an Italian father and an American mother Malfatti was born in São Paulo and went through there schooling. Early on, she showed interest in painting, which was sponsored by her mother. A congenital atrophy of her right arm forced her to use for painting the left hand. 1910-1914 she held in Berlin, studied with Lovis Corinth, visited 1912 Sonderbundausstellung in Cologne and was interested in the German Expressionism. After a short stay in Brazil in 1915, she traveled to New York, where he studied at the Independent School of Art and received insights into Cubism.
From 12 December 1917 through to January 11, 1918 her first solo exhibition was held in São Paulo, under the title Modern painting, which led to sharp conflicts. While a critic their images with " drawings of the inmates of asylums " compared, it was defended by Oswald de Andrade, who was familiar with the works of futurist Marinetti.
Malfatti 1922 took part in the Semana de Arte Moderna ( "Week of Modern Art " ) in São Paulo and formed with Tarsila do Amaral, Mário de Andrade, Oswald de Andrade, and Menotti del Grupo dos Cinco Picchia the so-called ( " Group of Five " ). The time from 1922 applies brasileiro first phase of Modernism. With Mário de Andrade she shared a lifelong friendship.
From 1923, when she received a scholarship for a trip to Paris, she gave up the expressionism. In 1928 she returned to São Paulo, where she continued her artistic career led to more conventional kinds and especially portraits and still lifes painted.