Frederick was born on 3 June 1843 in the Yellow Palace in Copenhagen, as the eldest son and child of Prince Christian of Schleswig-Holstein-Sonderburg-Glücksburg and Princess Louise of Hesse-Kassel-Rumpenheim.
His father's family was a cadet branch of the Danish royal House of Oldenburg, which was descended from Christian III and which had ruled as non-sovereign dukes in Schleswig-Holstein for eight generations.
He had five younger siblings: Alexandra (1844-1925), William (1845-1913), Dagmar (1847-1928), Thyra (1853-1933) and Valdemar (1858-1939).

In 1853, it was clear that the main line of the Oldenburg dynasty would become extinct with King Frederick VII, who was elderly and childless.
Frederick's mother was very close to the succession, as she was a niece of the previous Oldenburg king, Christian VIII, through his sister.
With the other heirs from the House of Hesse-Kassel having renounced their claims to the Danish throne in favour of Louise, who in turn relinquished her own claim, his father was eventually chosen as the heir presumptive.
Accordingly, Frederick was created a Prince of Denmark.

After his confirmation in 1860, Prince Frederick was given an extensive military education, pursuing a career in the Royal Danish Navy alongside his brother William.
In 1863, Frederick was sent to study political science at the University of Oxford, but returned to Denmark upon his father becoming king in November that year.
As heir apparent to the throne, he was given a seat in the State Council and subsequently assisted his father in the duties of government.
In 1864, he formally took part in the Second Schleswig War against Prussia and Austria.

The crown prince was a member of the Danish Order of Freemasons, serving as its Grand Master from 1871 until his death.
Frederick was born on 3 June 1843 in the Yellow Palace in Copenhagen, as the eldest son and child of Prince Christian of Schleswig-Holstein-Sonderburg-Glücksburg and Princess Louise of Hesse-Kassel-Rumpenheim. His father's family was a cadet branch of the Danish royal House of Oldenburg, which was descended from Christian III and which had ruled as non-sovereign dukes in Schleswig-Holstein for eight generations. He had five younger siblings: Alexandra (1844-1925), William (1845-1913), Dagmar (1847-1928), Thyra (1853-1933) and Valdemar (1858-1939).
In 1853, it was clear that the main line of the Oldenburg dynasty would become extinct with King Frederick VII, who was elderly and childless. Frederick's mother was very close to the succession, as she was a niece of the previous Oldenburg king, Christian VIII, through his sister. With the other heirs from the House of Hesse-Kassel having renounced their claims to the Danish throne in favour of Louise, who in turn relinquished her own claim, his father was eventually chosen as the heir presumptive. Accordingly, Frederick was created a Prince of Denmark.
After his confirmation in 1860, Prince Frederick was given an extensive military education, pursuing a career in the Royal Danish Navy alongside his brother William. In 1863, Frederick was sent to study political science at the University of Oxford, but returned to Denmark upon his father becoming king in November that year. As heir apparent to the throne, he was given a seat in the State Council and subsequently assisted his father in the duties of government. In 1864, he formally took part in the Second Schleswig War against Prussia and Austria.
The crown prince was a member of the Danish Order of Freemasons, serving as its Grand Master from 1871 until his death.
Frederick VIII of Denmark