He is second in line to the throne of Denmark and Norway, although he is older than his second cousins, King Ingolf I and his brother, Prince Christian. He may not be expected to actually inherit the throne, however, his son, Prince Haakon, is expected to one day become King of Denmark and Norway. He is married since 29 August 1968 in Aarhus to Norwegian-born Sonja Haraldsen, and they have two children: Princess Martha Louisa, Countess Behn, and Prince Haakon.