Just before World War I, in 1913 Lya Mara moved with her family to Warsaw, as Poland and Latvia were part of the Russian Empire.

In Warsaw, Lya Mara played her first small part in a short fiction silent film under a characteristically simplified title We want husband (1916, as Mia Mara) and soon after in another film Bestia (The Beast, premiere on 5 January 1917) directed by a Polish director of older generation Alexander Hertz.

Another Polish actress, Pola Negri, who later made an extraordinary career in Germany and in America, was the star of this film.

Mara played important parts such as Charlotte Corday, Anna Karenina (1919) and Manon, attracting audiences with her charm and youthful appeal.

Mara could not adapt her acting to the new artistic conditions after the introduction of sound in cinema in 1929, while Zelnik became the first director in Germany who postsynchronized foreign films.