Simberg was born at Hamina (original Swedish Fredrikshamn) in Finland, the son of Colonel Nicolai Simberg and Ebba Matilda Simberg (born Widenius). In 1891, at the age of 18, he enrolled at the Drawing School of the Viipuri Friends of Art, and also studied at the Drawing School of the Finnish Art Association (Suomen Taideyhdistys) (1893–1895), but in 1895 decided to become the private pupil of Akseli Gallen-Kallela at his wilderness studio Kalela in Ruovesi. Between 1895 and 1897 he studied with Gallen for three periods. In 1896 Simberg went to London, and in 1897 to Paris and Italy. During these years he exhibited several works at the Finnish Artists' autumn exhibitions, including 'Autumn, Frost', 'The Devil Playing Music' and 'Aunt Alexandra' (1898), which were well received. Critical success led to his being made a member of the Finnish Art Association, and to his being appointed to teach at the Drawing School of the Viipuri Friends of Art. In 1904 he was commissioned to decorate the interior of Saint John's church in Tampere (now Tampere cathedral), a project which he carried out with Magnus Enckell between 1904 and 1906. From 1907 to 1917 Simberg taught at the Drawing School of the Finnish Art Association. He died at Ahtari in 1917.
The two characters Simberg used most frequently for his art are the "Poor Devil" and Death personified. Simberg's paintings emphasize mainly topics macabre or supernatural. A good example of this is his painting Kuolema kuuntelee ("Death Listens"). The painting depicts Death, personified as a skeleton wearing a black coat, listening with a bowed head as a young man plays the violin. In the background, there is an old woman lying on a bed, pale and apparently sickly. There is a suggestion that Death is there for the old woman, but that he is pausing so the young man, possibly the dying woman's son, can have time to finish his violin playing.
Hugo Simberg's frescoes at the Tampere Cathedral Simberg's famous painting The Wounded Angel, too, is somewhat gloomy, its titular character appearing in the shape of a winged angel with a bandaged head, borne on a stretcher by two somberly dressed boys, one of whom looks toward the viewer with a serious expression. The painting is the best known of the artist's works and is especially famous in Finland. The Finnish symphonic metal band Nightwish released on 11 August 2007 their latest music video, "Amaranth", which is based on this particular painting. Simberg was a print-maker and photographer as well as a painter. One of his early photographs, named 'Guido, Fish Boy', shows a boy sitting on a rock, looking out to sea. He made photographs and drawings of naked pre-pubesent boys, some carrying large wreaths. Images of wreath-carrying boys (frontal nudity not quite visible) are a motif of Simberg's frescoes in the Tampere Cathedral, painted between 1905 and 1906.