The order is found throughout the Commonwealth of Nations,[5] Hong Kong, the Republic of Ireland, and the United States of America,[6] with the worldwide mission "to prevent and relieve sickness and injury, and to act to enhance the health and well-being of people anywhere in the world.

[7]In the 1820s, those Knights of Malta residing in France granted knighthoods to certain people of various Christian denominations who provided support to the Order in England.

[9] This was to be achieved by issuing bonds in London to form a mercenary army of demobilised British soldiers using readily available, cheap war surplus.

A deal transferring various islands to the Order of Malta, including Rhodes when captured, was struck with the Greek rebels,[10] but, ultimately, the attempt to raise money failed when details leaked to the press, the French monarchy withdrew its backing of the Council, and the bankers refused the loan.

In June 1826, a second attempt was made to raise money to restore a Mediterranean homeland for the Order when Philippe de Castellane, a French Knight of Malta, was appointed by the Council to negotiate with supportive persons in Britain.

On 29 January 1831, in the presence of Philip de Castellane and the Agent-General of the French Langues, Peat was elected prior ad interim.

On 24 February 1834, three years after becoming prior ad interim, in order to publicly reaffirm his claim to the office of Prior and in the hope of reviving a charter of Queen Mary I dealing with the original English branch of the Order of Malta, Peat took the oath de fideli administratione in the Court of the King's Bench, before the Lord Chief Justice.

Dymoke sought to rectify this by seeking acknowledgement from the headquarters of the Roman Catholic Sovereign Military Order of Malta, but its then Lieutenant Grand Master, Philippe de Colloredo-Mansfeld, refused the request.

[6] Charles III is at the apex of the Order of St John as its Sovereign Head,[29] followed by the Grand Prior—since 1975, Prince Richard, Duke of Gloucester.

[58] Following constitutional changes made in 1999, the Priory of England and The Islands was established (including the Commandery of Ards in Northern Ireland) alongside the existing Priories of Wales, Scotland, Canada, Australia (including the Commandery of Western Australia), New Zealand, South Africa, and the United States.

[61] The Order of St John today constitutes part of the Canadian national honours system and the priory, established in 1946 out of the Commandery of Canada, is the largest outside of the United Kingdom,[62] with some 6,000 members.

As citizens of a country that did not have the sovereignty of the Order of St John vested in its head of state, American inductees who first joined the new priory were specifically asked to only "pay due obedience" to the governing authorities of the order "in all things consistent with your duty to your own country," thus eliminating any question of loyalty to a foreign head of state superseding American postulants' duties as US citizens.

[71] All members of the Order are also required to wear specific robes for formal occasions of the society, including a mantle, sopra vest, and hat.

The only other unique mantles are those of the Medical Officer of the St John Ophthalmic Hospital, which bears a special pattern,[72] and of chaplains, which is a black silk robe with full sleeves.

The secretaries of the order, the priors and the commanders also wear the badge superimposed upon two goose quill pens embroidered saltire-wise in white silk.

[72] The sopra (or supra) vest is a long drape of thin, black cloth that buttons close down the neck and to one side, falling to the ankles and cut so as to entirely cover the body.

Clerical inductees of the order may, when officiating, wear over their cassock and surplice a mozzetta of black with red lining, edging, and buttons, a 76mm wide star worn on the left breast and the accordant badge suspended at the neck.

[74] The Sovereign Head confirms all appointments to the order as he, in his absolute discretion, shall think fit,[75] though the constitution does impose certain limitations: the maximum number of members is set at 35,000,[76] and appointees may not be under the age of 18.

[78][79] To be inducted, new members must recite the organisation's declaration: I do solemnly declare that I will be faithful and obedient to The Order of St John and its Sovereign Head as far as it is consistent with my duty to my [sovereign/president] and to my country; that I will do everything in my power to uphold its dignity and support its charitable works; and that I will endeavour always to uphold the aims of this Christian order and to conduct myself as a person of honour.

The issue of the order's Christian character and the issue of "inclusive membership" was dealt with in the Grand Council's Pro Fide Report in 2005, wherein it was said that the order's life is shaped by Christian faith and values, but that "[r]ather than the emphasis being primarily upon 'spiritual beliefs or doctrine' it is on works of mercy rendered through St John".

"[82] Admission to or promotion within the Order of St John does "not confer any rank, style, title, dignity, appellation or social precedence whatsoever".