Around 1840, he was part of the emerging National Romantic landscape painting scene in Denmark but as a result of his over-dramatic and excessively natural style, he did not fit the aesthetics and the ideology of the period.

Posthumously, half a century after his death, his reputation was restored, prompted by the art historian Karl Madsen, and today he is considered to be one of the leading Danish landscape painters of his day, the peer of his more famous contemporaries P. C. Skovgaard and Johan Lundbye.

His parents were Jørgen Christian Dreyer, a successful merchant who had been the richest man in town until the national bankruptcy in 1813, and his third wife Caroline Dorthea (née Møller).

Under the supervision of his professors, J. L. Lund and Christoffer Wilhelm Eckersberg, he trained to become a history painter, the most prestigious artistic discipline at that time, and also painted some portraits.

[1] Several times he also sought out the small island of Brandsø in the Little Belt, the narrow strait between Funen and Jutland, where he found a near perfect landscape to his liking with dolmens and distant coasts.

Blicher's descriptions of the stark beauty of the vast, brown-colored heaths of mid Jutland, of its people and almost exotic dialects, had a mesmerizing effect on the painter.

Dreyer first visited the east coast around Aarhus in 1838 and later that year he was present when Blicher arranged his first National Awakening Meeting at Himmelbjerget.

In Denmark, people enthusiastically read Bernhard Severin Ingemann's historic novels and Adam Oehlenschläger while N. F. S. Grundtvig's sermons were drawing large crowds.

[1] Lundbye, Sjovgaard and Dankvart had for years preferred Danish subjects and became the leading proponents of the emerging era of National Romantic painting.

The art historian Karl Madsen reestablished Dreyer's reputation as one of the leading landscape artists of the day, on a par with Lundbye and Skovgaard, when commenting on two exhibitions in 1901 and 1912.