Melgaard was born in Sydney, Australia to Norwegian parents, and was raised in Oslo, Norway. In 2009, he moved permanently to New York. Melgaard studied at the Norwegian National Academy of Fine Arts, Rijksakademie in Amsterdam from 1991 to 1992 and at the Jan van Eyck Academie in Maastricht from 1992 to 1993.
Early in his career Melgaard created controversial installations referencing subversive subcultures such as S&M and heavy metal music. Currently, his practice consists of an emphasis on expressionistic paintings and drawings, often containing text. His first show in New York was in 2000, where he exhibited sculptures of apes engaged in sex acts. In January 2014, Melgaard’s artwork Chair sparked controversy. Chair is a sculpture of a bound black woman on her back with a seat cushion on her thighs, and is a reinterpretation of a similar piece by British pop artist Allen Jones. The controversy began when Russian art socialite Dasha Zhukova was photographed sitting on the cushion for a fashion website, sparking online accusations of racism under the Twitter hashtag #racistchair. Guardian critic Jonathan Jones suggested that this controversy was a misunderstanding of Melgaard’s intentions, and Zhukova said that the photograph of her was “out of context”; the artwork intended to be a “commentary on gender and racial politics”. Melgaard himself released a statement responding to the controversy that was labelled by some writers as “bizarre”.
Melgaard has collaborated with Norwegian artist Sverre Koren Bjertnaes in several exhibitions. The two alternate to work on the same canvas, giving them an expression neither of the artists would achieve alone.