Frederik was educated at the Danish Naval College and was made a sublieutenant in 1921. He loved being at sea and rose steadily through the ranks. In 1927, he was given his first command, of the torpedo boat Søhunden (The Sea Dog). As crown prince, he broke with a long-standing tradition in the Royal House by choosing the Navy over the Army. His long career as a naval officer was a core aspect of his life as king.

In 1935, Frederik (IX) married Princess Ingrid of Sweden, who was 10 years younger than him. They married in Stockholm, as it was traditional the hold the wedding in the bride’s home country. Shortly after the wedding, the newlyweds travelled to Copenhagen on the Royal Yacht Dannebrog. The couple had three daughters: Princess Margrethe, Princess Benedikte and Princess Anne-Marie. Frederik IX was a dedicated family man, and he and Queen Ingrid made the Royal House much more relatable to the Danish people, in part by inviting the media into the royal residence at Amalienborg and by sharing photos of their three daughters. Thus, Frederik IX, Queen Ingrid and the three princesses became familiar faces to everyone in Denmark.

Frederik (IX) became king on 20 April 1947 after the death of his father (Christian X). During his reign, Denmark underwent one of the most transformative and fastest transitions in history, from an agricultural society characterised by widespread scarcity to a prosperous welfare society. Concurrent with this change, Denmark’s policy of neutrality was replaced by an active policy of alliances, and as a result of the economic boom of the 1960s, women entered the labour market in much greater numbers than before. Frederik IX kept up with the times and soon became known as a modern king, adapting to contemporary society. Together, he and Queen Ingrid were able to strengthen the role of the monarchy as a unifying force during a time of great social and economic change. 

Frederik IX was known for his unpretentious, down-to-earth manner. He loved music and was an accomplished conductor who mastered a wide, classical repertoire. He never performed in public but often conducted at private events, including conducting the Royal Danish Orchestra, which every year gave The King a concert as a birthday gift. 

Frederik IX was the first king to give the TV-transmitted New Year’s addresses that continue to form an important connection between the sitting monarch and the Danish people to this day. 

In cooperation with Queen Ingrid, Frederik IX oversaw the transformation of the monarchy from a distant, elevated institution to a symbol of the growing equality in society that characterised modern society. He had a naturally warm and friendly way with people without losing the dignity of the office. His training in the demanding but informal environment of the navy, which he maintained a close life-long connection to, also contributed to his personal manner.