 For the following five years, he practiced the legal profession, participated in cultural activities (particularly in theater performances of the Rūta Society) and served as the chief editor of "Lietuvos ūkininkas" (1907–12), and another newspaper "Lietuvos žinios" (1910–12).When the German army occupied Lithuania in 1915, Sleževičius left for Russia.Sleževičius remained active with the Lithuanian community, participating in the activities of the Lithuanian Society to Help Those Suffering from War, touring Russia as its representative.