[1][2][full citation needed][3][4] A letter written by the Scottish author Robert Louis Stevenson in 1883 contains the phrase, "He's the real Mackay".
[4] In 1935, New Zealand mystery writer Ngaio Marsh presented a character in Enter a Murderer who muses whether gun cartridges used in a play were "the real Mackay.
[7] One theory is that railroad engineers looking to avoid inferior copies would request it by name, inquiring if a locomotive was fitted with "the real McCoy system".
"[10] In the 1996 documentary The Line King, caricaturist Al Hirschfeld attributed the phrase to his friend, 1930s pioneer radio host George Braidwood McCoy, who proved he could live off the land without paying for food or rent.
[13] In 1987, Country singer George Jones recorded a song called "The Real McCoy" on his album "Too Wild Too Long".
In the Disney Channel show, Hannah Montana, in the song "Gonna Get This", the phrase is used with Miley Cyrus singing the line, “The honest truth, the Real McCoy”.
In the title track of their 1986 album Music That You Can Dance To, the American pop band Sparks sang “Get yourself in tune for the real McCoy”.
In Star Trek: The Original Series, the episode "The Man Trap" by George Clayton Johnson featured a polymorphic alien that at one point looked like Dr. McCoy.
In the Akihabara Explosion event in the English version of the mobile game Fate/Grand Order, Katsushika Hokusai, impressed by the sheer number and workmanship of the dolls in the tower, refers to their maker, the King of Figures, as "the real McCoy" in terms of their skill and speed of sculpting.