Black and white publicity photo of actor Deforest Kelly as Dr. Leonard McCoy from the television show Star Trek (1966–69). A man in a Star Fleet uniform from the show standing in front of a control panel on the bridge of the starship USS Enterprise.
20 August 2021
[22 August: deleted several lines regarding the speculative origin of the phrase coming from the Scottish title Reay Mackay, which lacks evidentiary support.]
The real McCoy is the genuine article, the actual thing itself, not a fake or pretender.
The origin of the phrase is unknown, and hypotheses as to the origin abound, most of which can be dismissed because the phrase antedates the events in the explanation. Those that cannot be immediately dismissed have no evidence supporting them, being mere speculation.
The earliest known instance of the phrase is in the form the real Mackay and appears in the Scottish newspaper the Arbroath Guide of 12 February 1848. The story is about a con man who took a man’s hat, presumably an expensive one, ostensibly to refurbish it, but returned a cheap imitation:
The hat was shining and glossy, and, like the renovator, sleekit; and though some doubts were at first entertained as to its being the real Mackay, the lining having been recognized, all seemed right, the hat was accepted of, the shilling paid, when Quin with pantomimic rapidity disappeared. The sequel of the story of the hat need hardly be told. The hat given Ross as his own on farther examination proved not to be it at all, but a very inferior article, indeed not calculated to grace either kirk or market; but in which the ingenious Quin had contrived to place, we fear with a view to deceive, the lining which had appertained to that of which he had deprived his unlucky customer.
The phrase is unmarked (meaning the editor did not put it in italics or quotation marks), and the story is not about anyone named Mackay, so it appears that the phrase was at least somewhat common and familiar to Scottish readers by this date.
An 1856 news story about a different con game was widely reprinted in British newspapers. The version here is from the West Yorkshire Huddersfield Chronicle of 14 June 1856, but the original appears to have been in the Dundee Advertiser (Scotland), but I have been unable to locate that appearance. In the story, a man named M’Kay died leaving a sizeable fortune but apparently no heirs. A woman, Margaret M’Kay, claimed to be his out-of-wedlock daughter, and had the body exhumed so that the relationship could be determined through their similar facial features. This was done and the woman declared to be his daughter, when:
The churchyard tragedy turned out to be but a farce after all, for William, from Australia, stepped in and proved himself to be the old man’s only son and child now alive. The proofs produced by William were the letters which he had sent to his father from Australia, and the letters which he had received in return. From these letters it was perfectly apparent that he was the only surviving child of his father; and Margaret, who had so warmly wept over her father’s grave, was obliged at last to yield the day in favour of William, the “real M‘Kay,” who has now been decerned sold executor to his father by the sheriff.
Usually, when quotation marks are placed around a word or phrase, they indicate that the term is new, foreign, or otherwise unfamiliar. But here, given that the protagonists are actually named M’Kay, the quotation marks seem to be a case of signaling a known phrase being used to label a particularly apt use of it.
G. Mackay and Co. was also the name of a Scottish distillery, and a use of the phrase makes reference to that in an 1856 poem, Deil's Hallowe'en by a poet using the pseudonym Young Glasgow:
A drappie o' the real M'Kay.
In 1870, the distillers adopted the phrase as an advertising slogan, but it was, as we have seen, already firmly established as a catchphrase by this date.
The spelling real McCoy is first recorded in Canada, in James Bond’s (not that one) 1881 book The Rise and Fall of the “Union Club!”:
“But even if we get up the Club, where’ll we have it, Ned?”
“Where? Why over behind our place of course; you couldn’t find a better place. Don’t you mind the little beaver-meadow where got the white haws?—that’s where I’d laid out to have it.”
“By jingo! yes; so it will be. It’s the ‘real McCoy,’ as Jim Hicks says. Nobody but a devil can find us there.”
There are any number of other suggestions for the origin, and most commonly the names of boxer Norman Selby “Kid” McCoy (1873–1840) and Canadian-American inventor Elijah McCoy (1844–1929) are proffered as the putative origin. But as can be seen from the dates, not to mention the spelling of their names, they are too late and on the wrong continent to be the origin.
Sources:
Bond, James S. The Rise and Fall of the “Union Club!” or, Boy Life in Canada. Yorkville: Royal Publishing, 1881, 1. HathiTrust Digital Archive.
“County Court at Huddersfield” (syndicated). Huddersfield Chronicle (West Yorkshire, England), 14 June 1856, 8. Gale Primary Sources: British Library Newspapers.
Green’s Dictionary of Slang, 2021, s.v. real McCoy, the, n.
Oxford English Dictionary, third edition, March 2001, modified December 2020, s.v. McCoy, n. and adj.
“Police Court.” Arbroath Guide and Weekly Advertiser and Reporter (Scotland), 12 February 1848, 667. The British Newspaper Archive.
Scottish National Dictionary, 2005, s.v. Mackay, prop. n. Dictionaries of the Scots Language / Dictionars o the Scots Leid.
Photo credit: NBC Television Network, c.1966. Public domain image in the United States because it was published in the United States prior to 1977 without a copyright notice.