The phrase more people know Tom Fool than Tom Fool knows is used in a situation in which someone is recognised by a person or persons whom he or she does not know or recognise.

This phrase occurred, for example, in the column The Curmudgeon: Hugh Leonard’s Week, by the Irish playwright and essayist Hugh Leonard (1926-2009), published in the Sunday Independent (Dublin, County Dublin, Ireland) of 19^th May 2002:

I am both charmed and alarmed by the smallness of Dublin. In short order, we meet our favourite couple, Peter and Alicia White, and then bump into a lady we last met on New Year’s Eve. Next, because more people know Tom-Fool than Tom-Fool knows, I am hailed by a complete stranger. Finally, I encounter an old friend, a person of talent who was once a kind of Beau Brummell and now looks wretched and down at heel.

An earlier expression, similar to more people know Tom Fool than Tom Fool knows, but with the clown instead of Tom Fool, occurred in Wit and Fancy in a Maze. Or the incomparable Champion of Love and Beautie. A Mock-Romance. Imbellished with many rare and choyce Pieces of Drollery. And a Marginall Comment expounding the obscure things of the History. Written originally in the British Tongue, and made English by a person of much Honor (London: Printed by T. W. for Tho. Vere…, 1656), also titled Don Zara del Fogo: A Mock-Romance, by Samuel Holland:

Though it be true (said Soto) that in all Comedies more know the Clown, then the Clown knows, and though your Fame fill the Universe, this Lady yet may be one of those whose eares have not suckt in the report.

The earliest occurrences of the phrase more people know Tom Fool than Tom Fool knows that I have found are as follows, in chronological order:

1-: From The History and Remarkable Life of the truly Honourable Col. Jacque, commonly call’d Col. Jack, who was born a Gentleman, put ’Prentice to a Pick-Pocket, was Six and Twenty Years a Thief, and then Kidnapp’d to Virginia. Came back a Merchant; was Five times married to Four Whores; went into the Wars, behav’d bravely, got Preferment, was made Colonel of a Regiment, came over, and fled with the Chevalier, is still abroad compleating a Life of Wonders, and resolves to dye a General (London: Printed, and Sold by J. Brotherton […], T. Payne […], [&c.], 1723), by the English novelist and journalist Daniel Defoe (1660-1731):

It was no satisfaction to me that I knew not their Faces, for they might know mine for all that, according to the old English Proverb, that more knows Tom Fool, than Tom Fool knows.

2-: From The Conduct and Scandalous Behaviour of the Porters in Exchange Alley (London: Printed for Mrs. Dodd […], and to be had at Mrs. Nutt’s, and Mrs. Cook’s, [1750?]):

At one of our full Meetings, it was resolved once more, to try how the Doctor bore all the aforesaid bad Treatment, on which one of us (whom he knew not) went next Evening, and found him in a little Room by himself, Smoaking a Pipe; the Door being open, he went in and sat down at the other Table, and after a little while, said your Servant Sir, I think I know you, is not your Name Shepherd, and you ply in Change Alley don’t you? Yes Sir said he, tho’ I don’t know you, but there is more knows Tom-fool than Tom-fool knows.

3-: From the following advertisement, published in The Public Ledger. Or Daily Register of Commerce and Intelligence (London, England) of 15^th May 1760:

On Thursday next will be publish’d,
In Two Volumes, Price 5s. sewed, or 6s. bound,
THE
HISTORY of TOM FOOL.
“More know Tom Fool, than Tom Fool knows.”

Printed for T. Walker, opposite Fetter Lane, Fleet-Street.

4-: From A Dialogue between Fashion and Folly, at Court, published in The Town and Country Magazine; Or, Universal Repository of Knowledge, Instruction, and Entertainment (London, England) of May 1781:

Fashion. To my certain knowledge, he is the Editor of the Town and Country Magazine, and, I dare say, has come here to pick up a Tête à Tête, or some other fashionable intelligence—but he is my particular acquaintance, and, I venture to believe, would write nothing to my disadvantage.
Folly. Sir, once take a fool’s advice—make up to him, and intreat him not to promulgate the secret.
Editor. Folly—More knows Tom Fool than Tom Fool knows—instead of taking your silly advice, thro’ the channel of Fashion, I shall
‘Eye Nature’s Walk, shoot Folly as it flies,
‘And catch the Manners living as they rise.’

5-: From The Town-Talker. Number I, by ‘E.’, published in The Wit’s Magazine; Or, Library of Momus, being a Compleat Repository of Mirth, Humour, and Entertainment (London, England) of February 1784:

Many of my readers who have been, what is called, upon the town, must have observed various faces which they have met in all sorts of societies and places. Went they to the Opera? they were there. To the Pantheon? they were there. To the Puppet-shew? they were there. To the Gallows? they were there. So that, without ever being of these people’s acquaintance, or ever speaking to them, their physiognomies were become more familiar to their recollection than those of their most intimate friends; and they seemed to haunt them more assiduously than even their wives or creditors, or any other disagreeable persons whatsoever. These omnipresent people are likewise equally remarkable for the extent of their acquaintance: they speak to every-body, know every-body; and will, upon the slightest invitation, very obligingly give you the history of every-body; yet ask any-body who they themselves are, and nobody knows. There is a proverb (I am much addicted to proverbs) which says, ‘More people know Tom Fool than Tom Fool knows:’ but the persons above described totally reverse this ancient adage; for they may very justly say, ‘Tom Fool knows more people than know Tom Fool.’