Schack was born at Brüsewitz near Schwerin. Having studied jurisprudence (1834–1838) at the universities of Bonn, Heidelberg and Berlin, he entered the Mecklenburg state service and was subsequently attached to the Kammergericht in Berlin. Tiring of official work, he resigned his appointment, and after travelling in Italy, Egypt, and Spain, was attached to the court of the grand duke of Oldenburg, whom he accompanied on a journey to the East. On his return he entered the Oldenburg government service, and in 1849 was sent as envoy to Berlin. In 1852 he retired from his diplomatic post, resided for a while on his estates in Mecklenburg and then travelled in Spain, where he studied Moorish history.