Grand Duke Jean's reign, which lasted from 1964 to 2000, was a pivotal period in Luxembourg's contemporary history. Marked by political stability, the modernisation of the country and a firm commitment to European integration, his reign oversaw the Grand Duchy's economic development and rise to prominence on the international stage. A discreet but deeply committed head of state, Jean embodied a monarchy that was close to the people and attentive to the changes of its time.

Prince Jean was born on 5 January 1921 at Berg Castle. His parents, Grand Duchess Charlotte and Prince Felix of Bourbon-Parma, chose his first names with care: Jean, in homage to Count Jean the Blind, an emblematic figure in Luxembourg's history; Benoît, in reference to Pope Benedict XV; and Guillaume, a traditional name of the House of Nassau.

Initially, he was educated at home. Jean was entrusted to the care of Marie-Louise Knaff, the Joffer who, from an early age, instructed the prince - and later his sisters Elisabeth (1922–2011), Marie-Adélaïde (1924–2007), Marie-Gabrielle (1925–2023), Alix (1929–2019), and his brother Charles (1927–1977) - in the Luxembourgish language and customs. Jean also developed a passion for sports at a very young age, which led him to join the International Olympic Committee in 1946.

While still a child, he accompanied his parents on some of their public engagements and sometimes took on a ceremonial role - for example, at the christening of an aeroplane or at official parades - gradually becoming accustomed to his future representative duties. On 23 January 1933, he reviewed the Volunteer Corps of the Gendarmerie and Police for the first time alongside his father.

From 1934 to 1938, Prince Jean left Luxembourg for Great Britain and became a boarder at Ampleforth College in Yorkshire, a Benedictine school that demanded strict discipline from its pupils - an asset that would prove invaluable during his military service in the Second World War.

On his return to Luxembourg, Jean received additional education from private tutors, including Pierre Frieden, the future Minister of State. In 1939, he came of age and, by Grand Ducal decree, was awarded the honorary title of Lieutenant of the Luxembourg Armed Forces. As heir to the throne, his representative duties focused on events of national importance, notably the Centenary celebrations marking the 100th anniversary of Luxembourg's independence - a great display of patriotism that was followed only months later by the invasion of the country by German troops in May 1940. He also represented his mother abroad, as was the case at the World’s Fair in New York in August 1939, when he attended the inauguration of the Luxembourg pavilion alongside his father, Prince Felix, and met President Roosevelt.

Accompanied by their father, the princely children boarded the USS Trenton, which took them to Annapolis in the United States. After settling in Canada, Prince Jean enrolled at Laval University in Quebec, where he studied law, philosophy and political science, before the family embarked on a series of goodwill tours.

These journeys brought them to the American Midwest, where the Grand Duchess sought to mobilise financial resources and political support among the descendants of Luxembourgish immigrants. Before joining the war effort, Prince Jean worked alongside other members of his family to promote the Luxembourg cause on the American continent. Accompanied by Guy Konsbruck, the family’s aide-de-camp, he travelled to Brazil in June 1942, where he met with descendants of Luxembourgish emigrants. He also took part in an NBC broadcast under the patronage of the Council for Democracy, alongside other members of royal families in exile. Later, after moving to England for his military training, he addressed Luxembourg’s youth on BBC radio in July 1943, urging them to remain united and persevere.

After a visit to the White House in 1942, it was agreed that Jean and his father, Prince Felix, would join the British Army. This decision followed the Nazi regime’s introduction of compulsory conscription for young Luxembourgish men. In November 1942, Prince Jean enlisted in the British Army, serving in the Irish Guards regiment. He began his training in Caterham and Pirbright before continuing at the Royal Military Academy Sandhurst.

Promoted to lieutenant in March 1944, Prince Jean was sent in secret to Eastbourne before his regiment landed in Normandy on 11 June as part of a reinforcement unit. Over the following months, he took part in some of the most critical campaigns of the war: the liberation of Caen, the Allied advance through France and the liberation of Brussels in September 1944. On the afternoon of 10 September, he entered Luxembourg, where he was reunited with his father. The two princes were cheered in Place Guillaume II, and Felix waved the national flag from the first-floor window of the Town Hall.

Prince Jean then rejoined his unit for Operation Market Garden and the Battle of the Bulge. He also took part in the offensive against the Siegfried Line and the capture of the Reichswald, advancing into Germany until the end of the war. Recalled to Luxembourg in April 1945 for the return of Grand Duchess Charlotte, he later continued his military service. A colonel in the Irish Guards, he remained with the regiment until his demobilisation in June 1947.

At the same time, Prince Jean took on an increasing number of ceremonial and institutional duties, representing Luxembourg at major international events such as the wedding of the future Queen Elizabeth and Prince Philip Mountbatten in 1947, and presenting a gold medal to Luxembourg athlete Josy Barthel, winner of the 1500 metres at the Helsinki Olympic Games in 1952.

Their wedding took place on 9 April 1953 in Notre-Dame Cathedral in Luxembourg City. The couple resided at Betzdorf Castle, where their five children were born: Princess Marie-Astrid (1954), Prince Henri, the future Grand Duke (1955), Prince Jean (1957), Princess Margaretha (1957) and Prince Guillaume (1963). The birth of the latter was announced to Jean by telegram while he was on a state visit to Washington, D.C.

In preparation for his future reign, Prince Jean gradually became involved in Luxembourg's institutional life. In 1951, he was appointed to the Council of State, enabling him to deepen his knowledge of the legislative process. On 4 May 1961, he was named Lieutenant-Représentant of Grand Duchess Charlotte. The Grand Ducal decree of 28 April declared:

As Head of State, Jean represented his country on numerous State and official Visits, both abroad and at home. During his reign, he undertook around sixty such visits, notably to the Vatican and Brazil (1965), Belgium (1967), the United Kingdom (1972), the USSR (1975), China (1979), the United States (1984) and Japan (1999). During his visit to the United Kingdom, he was made a Knight of the Order of the Garter, the highest British distinction.

In 1985, he and Grand Duchess Joséphine-Charlotte welcomed Pope John Paul II to Luxembourg - a visit of major symbolic significance for the country's Catholic population. The following year, in 1986, Grand Duke Jean received the Charlemagne Prize in recognition of Luxembourg's contribution to European integration. In 1990, he reaffirmed Luxembourg's unwavering support for a united and cooperative Europe in a speech before the European Parliament.

Throughout his reign, Grand Duke Jean ensured that he remained close to the Luxembourgish people. His compassion was evident in 1993, when he visited communities devastated by dramatic floods, offering comfort and reassurance to the victims. In his annual addresses, he regularly spoke about key themes such as human rights, youth, the economy, the environment, national identity and European unification. With a measured tone, yet mindful of contemporary social issues, he consistently emphasised the importance of preserving the country's culture and values.

On the political front, Grand Duke Jean presided with calm continuity over the transitions of power between successive Prime Ministers: Gaston Thorn in 1974, Pierre Werner in 1979, Jacques Santer in 1984 and Jean-Claude Juncker in 1995.

The year 1990 marked the centenary of the Luxembourg national dynasty. The programme of celebrations included the inauguration of the Monument to Grand Duchess Charlotte on Place Clairefontaine and a commemorative ceremony in Weilburg attended by Queen Beatrix of the Netherlands, underlining the dynastic ties between the two royal houses.

The closing years of his reign were marked by commemorations of the Second World War. In 1992, he took part in ceremonies marking the fiftieth anniversary of the general strike, and in 1994 he attended the fiftieth anniversary of the Normandy landings, where he stood as the only Head of State present to have fought in the conflict.

In this role, he chaired numerous meetings of the Luxembourg Boy Scout Association (LBSA) council and took part in many Scout activities, including Jubica 82, an international camp in Betzdorf that brought together more than 3,300 Scouts from 24 countries across four continents. In 1995, in recognition of his outstanding service to the Scout Movement, he was awarded the Bronze Wolf - the highest distinction granted by the World Organization of the Scout Movement.

Despite stepping back from official duties, Grand Duke Jean continued to represent Luxembourg at major commemorations, notably the 70th anniversary of the Normandy landings on 6 June 2014 in Ouistreham.

A great lover of nature, he retained a keen interest in environmental issues and the preservation of flora and fauna. His retirement years allowed him to travel around the country, visiting churches and chapels, walking through the Moselle vineyards and forests, and spending time in his favourite places: the Remerschen nature reserve, where he enjoyed birdwatching, and the Pont Misère in Esch-sur-Sûre, with its sweeping views of the lake. He was also a devoted follower of the Tour Cycliste de Luxembourg and cultivated personal interests such as photography and painting.

In January 2016, his 95th birthday was marked with great ceremony. Several hundred dignitaries, representatives from politics, business, culture and other royal families attended a gala concert held in his honour at the Philharmonie.

Grand Duke Jean died of pneumonia on 23 April 2019, at the age of 98. Thousands of Luxembourgers paid their last respects as they filed past his coffin, which lay in state at the Grand Ducal Palace. He was laid to rest alongside his wife, Grand Duchess Joséphine-Charlotte, in the Grand Ducal Crypt of Notre-Dame Cathedral in Luxembourg City.