"Another possible figure who could plausibly have been the source of the phrase is the political organizer Edward J. Flynn. He was a campaign manager for the Democratic party during the 1930s and 40s and was well-known to be highly effective at arranging political successes.
Such Machiavellian organizers were known as bosses. Flynn, with some irony, called his autobiography 'You're the Boss', in a reference to the American voting public. Edward J. Flynn had not been associated with the phrase 'in like Flynn' prior to the efforts by etymologists to explain it though and no records from the 1940s make any such link.
It seems very much more likely that Errol Flynn is the Flynn in question and, although the phrase may have been used before he was at the peak of his celebrity, it became well-known by association with him."
Bagster
“In Like Flint” is listed in the urban dictionary. I won’t post the meaning cos it casts linguistic aspersions upon the speaker, but it basically means whoever used it misspoke and they really meant to say “In Like Flynn”.
It was Errol Flynn, without a doubt. He was a legendary swordsman both on screen and off.
Ever hear the expression “In a New York minute?”
That one is TOTALLY WRONG too. It should always be: “In a New York second.”
It originated in New York in the ‘70s, referring to how fast one could flip a New York second mortgage, a common real estate investor play at the time.