Already at an early age Carla Colsmann Mohr began her education at Tegneskolen for Kvinder which was run by the artists, Charlotte Sode (1859–1931) and Julie Meldahl (1861–1946). In 1904, at the age of 17, she was accepted at Kunstskolen for Kvinder, which in 1908 merged with The Academy. Here she studied under, amongst others, the painter, Viggo Johansen (1851–1935), and continued her education until 1912. The influence from Viggo Johansen is visible in many of Mohrs early works, but at the end of her time at the academy she developed her own particular style during her travels to France and The Netherlands and later Italy. She built up her landscapes with small dense brushstrokes giving her paintings an almost mosaic-like quality.

Mohr exhibited nationally at Charlottenborgs Forårs- og Efterårsudstilling and at Den Frie Udstillingsbygning, and she furthermore exhibited several times internationally in Sweden and Berlin. Mohr fought for better working conditions for women artists in general, she was a member of Kvindelige Kunstneres Samfund and ran her own art school during the years 1914–1928. Later on she founded a grant in her own name, for a number of years bestowing grants upon women artists.