Kross has since worked in both German and English speaking film roles, including War Horse, Race and Into the White.

His career started with a small appearance in the 2002 film Hilfe, ich bin ein Junge (English: Help, I'm a Boy!).

[citation needed] In 2005, Kross came to the attention of Detlev Buck through his daughter, Bernadette, and he auditioned for Tough Enough (Knallhart);[3] Buck hired Kross to play the lead,[4] a 15-year-old boy who moves with his mother from a rich neighborhood of Berlin (Zehlendorf) to the Neukölln area, known at the time for its high number of Turkish immigrants and high crime level.

In the fall of the same year, he started shooting a film by Marco Kreuzpaintner, Krabat (The Satanic Mill).

In this version of Otfried Preußler's children's book, Kross plays the title role, one of the apprentices of magic, with co-stars Daniel Brühl and Robert Stadlober.

In Stephen Daldry's adaption of the best-selling novel by Bernhard Schlink about the relationship between a teenage boy and an older woman, Kross plays the lead role of Michael Berg, opposite Kate Winslet, Ralph Fiennes, and Bruno Ganz.

Kross has expressed no desire to move to Hollywood, preferring to stay in Germany and continue making both German and English language films.