Lago made her feature film debut in Miserable Life (2000),[3] providing the voice to Bea.

In 2002 she starred in Carol's Journey, a film directed by Imanol Uribe for which Lago was nominated for a Goya Award for Best New Actress.

[5] She won the 'Best New Talent in Spanish Cinema' awarded by L'Oreal in the 2008 56th San Sebastian Film Festival.

[8] Lago appears in the 2015 film Extinction[9] along with Matthew Fox and Jeffrey Donovan, in an adaptation of Juan de Dios Garduño's bestseller book Y pese a todo.

In March 2017 she started a vegan diet due to an ethical and environmental decision that gives her "peace of mind", she also says that she feels "full of energy" and is "perfect" in health.