At the same time as he gained access to Christoffer Wilhelm Eckersberg's painting school, he visited the Royal Danish Academy of Fine Arts from 1835 to 1840 and won both its silver medals.

[2] From 1844 to 45, Schack was given two years of travel support for the academy for France and Sardinia–Piedmont;[3] he had also been commissioned to produce an altarpiece, Christi Bjærgprædiken, which was only delivered after the king's death,[3] and a large picture for Christian VIII's and Queen Caroline Amalie's Coronation.

Schack later published a couple of volumes of Physiognomic Studies (1858–59), in which his best qualities as an artist were associated with a spirited gift of production as a writer.

Their daughter Laura Cathrine Marie Schack married the painter Ole Pedersen on 28 November 1890 in Copenhagen.

There is a self-portrait from 1859 (formerly in Johan Hansen's collection), a pen drawing by Vilhelm Rosenstand ( Camp scene ) 1863 (Frederiksborg Museum), a portrait of the woodcuts Fallen Officers in 1864 and Fallen at Dybbøl, a woodcut drawing in 1864 by Henrik Olrik and a Lithograph in 1867 by Edvard Fortling.