During the years 1894–1897 Lizzy studied at the Amsterdam Royal Academy of Visual Arts. Here she studied with the professors August Allebé, Nicolaas van der Waay and Carel Dake.
She also wrote two books for children, `n Vruchtenmandje (A little fruit basket), published in 1927, and Tante Tor is jarig (Aunt Tor has her birthday). This booklet, published in 1950, was illustrated by Nelly Bodenheim.
Besides portrait painting, Ansingh gained Celebrity for painting dolls, in which she was also encouraged by her aunt Thérèse Schwartze. She purchased a circa 1740-1750 dollhouse (or poppenhuis) in which she arranged her dolls for inspiration, as well as furnishing it with numerous other articles she collected. Her Amsterdam studio in the Herengracht, along with the dollhouse, was severely damaged on the night of 27 April 1943 when a British bomber was shot down, destroying the Carlton Hotel and much of the Reguliersdwarsstraat alongside her studio (the ensuing fire was the most devastating in Amsterdam since 1659 and is recorded in Anne Frank's diary). The dollhouse has since been restored and can be seen at the Museum Arnhem.
At the Academy a lasting friendship was born between a group of female Painters, later called the Amsterdamse Joffers: Lizzy Ansingh, Marie van Regteren Altena, Suze Bisschop-Robertson, Coba Ritsema, Ans van den Berg, Jacoba Surie, Nelly Bodenheim, Betsy Westendorp-Osieck and Jo Bauer-Stumpff. The importance of the Amsterdamse Joffers lies primarily in functioning as role Models for younger female Painters in the Netherlands, especially during and after the 1970s.