Prince Carl was born on 3 August 1872, in Charlottenlund Palace near Copenhagen.
He was the second son of Frederick, Crown Prince of Denmark (the future King Frederick VIII), and his wife Louise of Sweden.
His father was the eldest son of King Christian IX and Louise of Hesse-Kassel, and his mother was the only daughter of King Charles XV of Sweden (who was also king of Norway as Charles IV), and Louise of the Netherlands.
He was baptised at Charlottenlund Palace on 7 September 1872 by the Bishop of Zealand, Hans Lassen Martensen.
He was baptised with the names Christian Frederik Carl Georg Valdemar Axel, and was known as Prince Carl (namesake of his maternal grandfather the King of Sweden-Norway).

Prince Carl belonged to the Schleswig-Holstein-Sonderburg-Glücksburg branch of the House of Oldenburg.
The House of Oldenburg had been the Danish royal family since 1448; between 1536 and 1814 it also ruled Norway, which was then part of the Kingdom of Denmark-Norway.
The house was originally from northern Germany, where the Glucksburg (Lyksborg) branch held their small fief.
The family had permanent links with Norway beginning from the late Middle Ages.
Several of his paternal ancestors had been kings of independent Norway (Haakon V of Norway, Christian I of Norway, Frederick I, Christian III, Frederick II, Christian IV, as well as Frederick III of Norway who integrated Norway into the Oldenburg state with Denmark, Schleswig and Holstein, after which it was not independent until 1814).
Christian Frederick, who was King of Norway briefly in 1814, the first king of the Norwegian 1814 constitution and struggle for independence, was his great-granduncle.

Prince Carl was raised in the royal household in Copenhagen and educated at the Royal Danish Naval Academy from 1889 to 1893, graduating as a second lieutenant in the Royal Danish Navy.
In 1894 he was promoted to the rank of first lieutenant and remained in service with the Royal Danish Navy until 1905.

At Buckingham Palace on 22 July 1896, Prince Carl married his first cousin Princess Maud of Wales, youngest daughter of the future King Edward VII of the United Kingdom and his wife, Princess Alexandra of Denmark, eldest daughter of King Christian IX and Princess Louise.
Their son, Prince Alexander, the future Crown Prince Olav (and eventually king Olav V of Norway), was born on 2 July 1903.
Prince Carl was born on 3 August 1872, in Charlottenlund Palace near Copenhagen. He was the second son of Frederick, Crown Prince of Denmark (the future King Frederick VIII), and his wife Louise of Sweden. His father was the eldest son of King Christian IX and Louise of Hesse-Kassel, and his mother was the only daughter of King Charles XV of Sweden (who was also king of Norway as Charles IV), and Louise of the Netherlands. He was baptised at Charlottenlund Palace on 7 September 1872 by the Bishop of Zealand, Hans Lassen Martensen. He was baptised with the names Christian Frederik Carl Georg Valdemar Axel, and was known as Prince Carl (namesake of his maternal grandfather the King of Sweden-Norway). 
Prince Carl belonged to the Schleswig-Holstein-Sonderburg-Glücksburg branch of the House of Oldenburg. The House of Oldenburg had been the Danish royal family since 1448; between 1536 and 1814 it also ruled Norway, which was then part of the Kingdom of Denmark-Norway. The house was originally from northern Germany, where the Glucksburg (Lyksborg) branch held their small fief. The family had permanent links with Norway beginning from the late Middle Ages. Several of his paternal ancestors had been kings of independent Norway (Haakon V of Norway, Christian I of Norway, Frederick I, Christian III, Frederick II, Christian IV, as well as Frederick III of Norway who integrated Norway into the Oldenburg state with Denmark, Schleswig and Holstein, after which it was not independent until 1814). Christian Frederick, who was King of Norway briefly in 1814, the first king of the Norwegian 1814 constitution and struggle for independence, was his great-granduncle.
Prince Carl was raised in the royal household in Copenhagen and educated at the Royal Danish Naval Academy from 1889 to 1893, graduating as a second lieutenant in the Royal Danish Navy. In 1894 he was promoted to the rank of first lieutenant and remained in service with the Royal Danish Navy until 1905.
At Buckingham Palace on 22 July 1896, Prince Carl married his first cousin Princess Maud of Wales, youngest daughter of the future King Edward VII of the United Kingdom and his wife, Princess Alexandra of Denmark, eldest daughter of King Christian IX and Princess Louise. Their son, Prince Alexander, the future Crown Prince Olav (and eventually king Olav V of Norway), was born on 2 July 1903.
Haakon VII of Norway