Franz Lerch studied under Josef Jungwirth and Karl Sterrer at the Academy of Fine Arts in Vienna from 1919 to 1927. He became a master student of Alois Delug in 1922. Afterwards, he went on study trips to Paris and Holland. In 1927, he joined the Hagenbund artists’ association and participated regularly in their exhibitions. He began exhibiting internationally in 1930, when his painting Lovers was included in the Modern Austrian Painting exhibition at the University of Chicago alongside works by Alfred Kubin and Egon Schiele. He was awarded the Austrian State Prize several times, and in 1931 was awarded prizes by the City of Vienna and the Julius Reich Foundation.
In 1933 he married Stephanie Krauss, an author of children’s books. In 1939, Lerch and his wife emigrated to New York, both because she faced persecution by the Nazis for being Jewish, and because he wanted the freedom to be able to express himself in his art. He took a job at the Printex design company in 1942, and was only able to paint in his free time. He nevertheless took part in numerous exhibitions in New York. In 1946, Lerch joined the Vienna Secession, and in 1958 he took part in an exhibition of the Secession at the Historical Museum in Vienna alongside Franz von Zülow.