All executive authority is vested in the monarch, and royal assent is required for the National Assembly of Saint Kitts and Nevis to enact laws and for letters patent and Orders in Council to have legal effect.

Most of the powers are exercised by the elected members of parliament, the ministers of the Crown generally drawn from amongst them, and the judges and justices of the peace.

The Crown today primarily functions as a guarantor of continuous and stable governance and a nonpartisan safeguard against the abuse of power.

[4] Following the flag-raising ceremony after midnight, the Princess read a message from her sister, the Queen, and formally handed over the constitutional volumes to the Prime-Minister designate, Kennedy Simmonds.

Despite sharing the same person as their respective monarch, each of the Commonwealth realms — including Saint Kitts and Nevis — is sovereign and independent of the others.

[6] The monarchy thus ceased to be an exclusively British institution and in Saint Kitts and Nevis became a national, or "domesticated" establishment.

[7][8] This division is illustrated in a number of ways: The sovereign, for example, holds a unique title in relation to Saint Kitts and Nevis and, when he is acting in public specifically as a representative of the country, he uses, where possible, symbols of Saint Kitts and Nevis, including the country's national flag, unique royal symbols, and the like.

This is done in reciprocation to the sovereign's Coronation Oath, wherein they promise to govern the peoples of their realms, "according to their respective laws and customs".

This legislation limits the succession to the natural (i.e. non-adopted), legitimate descendants of Sophia, Electress of Hanover, and stipulates that the monarch cannot be a Roman Catholic, and must be in communion with the Church of England upon ascending the throne.

Though these constitutional laws, as they apply to Saint Kitts and Nevis, still lie within the control of the British parliament, both the United Kingdom and Saint Kitts and Nevis cannot change the rules of succession without the unanimous consent of the other realms, unless explicitly leaving the shared monarchy relationship; a situation that applies identically in all the other realms, and which has been likened to a treaty amongst these countries.

[21] The monarch's, and thereby the viceroy's role is almost entirely symbolic and cultural, acting as a symbol of the legal authority under which all governments and agencies operate, while the Cabinet directs the use of the Royal Prerogative, which includes the privilege to declare war, maintain the King's peace, and direct the actions of the Saint Kitts and Nevis Defence Force, as well as to summon and prorogue parliament and call elections.

The governor-general, on behalf of the monarch, also accredits Saint Kitts and Nevis High Commissioners and ambassadors and receives diplomats from foreign states.

[27] The viceroy additionally summons, prorogues, and dissolves parliament; after the latter, the writs for a general election are usually dropped by the governor-general at Government House, Basseterre.

[26] Thus, bills begin with the phrase: "Be it enacted by the King's Most Excellent Majesty, by and with the advice and consent of the National Assembly of Saint Christopher Nevis and by the authority of the same as follows".

[29] The Royal Assent, and proclamation, are required for all acts of parliament, usually granted or withheld by the governor-general, with the Public Seal of Saint Christopher and Nevis.

[35] The governor-general, on behalf of the monarch of Saint Kitts and Nevis, can also grant immunity from prosecution, exercise the royal prerogative of mercy, and pardon offences against the Crown, either before, during, or after a trial.

[48] The National Awards Committee is responsible for submitting nominations for the candidates to the office of the prime minister, which then forwards the recommendations to the governor-general.

St Edward's Crown appears on Saint Kitts and Nevis Defence Force badges and rank insignia, which illustrates the monarchy as the locus of authority.

Under The Police Act, 2002, the oath of allegiance, is:[55] "I, (name), do swear that I will well and truly serve Our Sovereign Lord the King in the office of Special Constable in the Federation without favour or affection, malice or ill-will, and that I will cause His Majesty's peace to be preserved, and will prevent to the utmost of my power offences against the same.

[56][57] A crown is also used to illustrate the monarchy as the locus of authority, appearing on defence and police force, postal workers, prison officers rank insignia.

[58] Under the Saint Christopher and Nevis Citizenship Act, new citizens of the country have swear allegiance to the monarch, and his heirs and successors.

And I need hardly say how very touched we have been by the welcome we have received on both islands and, for my part, it has been particularly special to return to places that I have such fond memories of visiting when I first came here some forty-six years ago during my time in the Royal Navy.

[65] In September 1993, Prince Philip, Duke of Edinburgh visited the country as the Queen's personal representative on the occasion of 10th anniversary of independence.

The couple met with Governor-General Sir Cuthbert Sebastian, Prime Minister Denzil Douglas, and other dignitaries, watched cultural shows, and the Earl unveiled a plaque commemorating the Diamond Jubilee and officially designated the Basseterre Valley Park as the Royal Basseterre Valley Park.

The Prince arrived on 23 November, and was welcomed by a military parade at Port Zante, and later attended a youth rally at Brimstone Hill Fortress.

Prince Harry then travelled by boat to Charlestown Pier on the neighbouring island of Nevis, where he visited a local turtle conservation initiative on Lovers Beach.

At the National Museum, they learnt more about the history of Saint Kitts and Nevis and signed a scroll to mark the Royal visit and the building's 125th anniversary.

The Duchess visited Hermitage Plantation House, where she met local women, and viewed an arts and craft display.

[73] A 2023 opinion poll found that 52% supported keeping the monarchy whilst 45% preferred Saint Kitts and Nevis to become a republic.