All executive authority is vested in the monarch, and royal assent is required for the Parliament of Saint Lucia 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.

[1] Saint Lucia continues to cherish and benefit from its long standing relationship with the monarchy which has taken this island from colonialism through Associated Statehood and now Independence.Princess Alexandra represented the Queen at the independence celebrations in 1979.

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

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 Lucia, still lie within the control of the British parliament, both the United Kingdom and Saint Lucia 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.

[14] On my assuming office, I chose as my Mission Statement to truly and faithfully represent the Sovereign in Saint Lucia in accordance with the provisions of the Constitution, to foster national unity and identity at home and abroad, to promote our national economic, cultural and social interests and to encourage excellence in all fields of endeavours.The Constitution of Saint Lucia is made up of a variety of statutes and conventions which gives Saint Lucia a parliamentary system of government under a constitutional monarchy, wherein the role of the monarch and governor-general is both legal and practical, but not political.

All institutions of government act under the sovereign's authority; the vast powers that belong to the Saint Lucian Crown are collectively known as the Royal Prerogative.

[18] 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, and maintain the King's peace, as well as to summon and prorogue parliament and call elections.

The monarch, and by extension the governor-general, also accredits Saint Lucian High Commissioners and ambassadors,[23] and receives diplomats from foreign states.

[24][25] In foreign policy, the monarch acts solely on the advice of the respective realm government, which can sometimes lead to anomalies in diplomatic recognition.

[30] The viceroy additionally summons, prorogues, and dissolves parliament;[31] after the latter, the writs for a general election are usually dropped by the governor-general at Government House, Castries.

[33] A pledge of loyalty and allegiance to the monarch by members of the House of Assembly and the Senate, coincides with the opening of a session of Parliament.

[35] 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 House of Assembly and the Senate of Saint Lucia, and by the authority of the same, as follows".

[36] 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 Lucia.

[42] The governor-general, on behalf of the monarch of Saint Lucia, 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.

[51] Several members of the royal family have visited Saint Lucia over the years to highlight some key moments in the country's history.

In 1985, the Queen laid the foundation stone for the new Red Cross headquarters and visited residential homes for the elderly and schools.

[56] In 2012, the Earl and Countess of Wessex, visited the country to mark the Queen's Diamond Jubilee, and took part in the independence anniversary celebrations.

[58] Charles, Prince of Wales visited in 2019 to celebrate the 40th anniversary of Saint Lucia's independence, and watched a ceremony and military parade in Castries.