The son of a carpenter, Olaf August Hermansen was born in 1849 in Frederiksberg, Denmark. He was an apprentice porcelain painter at Bing & Grøndal and studied painting at the Royal Danish Academy from 1872 to 1876. In addition to his floral paintings, Hermansen supported himself by decorating terracotta works for P. Ipsens Enke. He routinely exhibited his works at the Academy and received several awards.