He was born in Copenhagen the youngest son of Prince Valdemar of Denmark and Princess Marie of Orléans.

[2] His father was a younger son of King Christian IX of Denmark and Louise of Hesse-Kassel, and his mother was the eldest daughter of Prince Robert, Duke of Chartres and Princess Françoise of Orléans.

[3] He was christened on 24 February 1894 and his godparents were: King Christian IX and Queen Louise of Denmark (his paternal grandparents); Prince Christian of Denmark (his paternal first cousin); Prince George of Greece and Denmark (his paternal first cousin); Grand Duke Adolphe and Grand Duchess Adelheid-Marie of Luxembourg; Anna, Landgravine of Hesse; and Princess Marie of Anhalt.

[6] As became customary in the Danish royal house upon marriage to a commoner, prior to the wedding Viggo renounced his place in Denmark's line of succession to the Crown, forfeiting his title of Prince of Denmark, and his style of Royal Highness.

[7] With the king's authorisation, he assumed the title "Prince Viggo, Greve af (Count of) Rosenborg" and the style of Highness on 21 December 1923.