The longest and closest connection was that with Hamilton. This very young and obscure officer attracted Washington's attention in the campaign of 1776, early in the next year was appointed to the staff, and quickly became so much a favorite that Washington spoke of him as "my boy." Whatever friendliness this implied was not, however, reciprocated by Hamilton. After four years of service, he resigned, under circumstances to which he pledged Washington to secrecy, and then himself, in evident irritation, wrote as follows:

"Two days ago, the General and I passed each other on the stairs. He told me he wanted to speak to me. I answered that I would wait upon him immediately. I went below, and delivered Mr. Tilghman a letter to be sent to the commissary, containing an order of a pressing and interesting nature. Returning to the General, I was stopped on the way by the Marquis de Lafayette, and we conversed together about a minute on a matter of business. He can testify how impatient I was to get back, and that I left him in a manner which, but for our intimacy would have been more than abrupt. Instead of finding the General, as is usual, in his room, I met him at the head of the stairs, where, accosting me in an angry tone, 'Colonel Hamilton,' said he 'you have kept me waiting at the head of the stairs these ten minutes. I must tell you, sir, you treat me with disrespect.' I replied without petulancy, but with decision: 'I am not conscious of it, sir; but since you have thought it necessary to tell me so, we part.' 'Very well, sir,' said he, 'if it be your choice,' or something to this effect, and we separated. I sincerely believe my absence, which gave so much umbrage, did not last two minutes. In less than an hour after, Tilghman came to me in the General's name, assuring me of his great confidence in my abilities, integrity, usefulness, etc, and of his desire, in a candid conversation, to heal a difference which could not have happened but in a moment of passion. I requested Mr Tilghman to tell him—1st. That I had taken my resolution in a manner not to be revoked ... Thus we stand ... Perhaps you may think I was precipitate in rejecting the overture made by the General to an accomodation. I assure you, my dear sir, it was not the effect of resentment; it was the deliberate result of maxims I had long formed for the government of my own conduct.... I believe you know the place I held in the General's confidence and counsels, which will make more extraordinary to you to learn that for three years past I have felt no friendship for him and have professed none. The truth is, our dispositions are the opposites of each other, and the pride of my temper would not suffer me to profess what I did not feel. Indeed, when advances of this kind have been made to me on his part, they were received in a manner that showed at least that I had no desire to court them, and that I desired to stand rather upon a footing of military confidence than of private attachment."

Had Washington been the man this letter described he would never have forgiven this treatment. On the contrary, only two months later, when compelled to refuse for military reasons a favor Hamilton asked, he said that "my principal concern arises from an apprehension that you will impute my refusal to your request to other motives." On this refusal Hamilton enclosed his commission to Washington, but "Tilghman came to me in his name, pressed me to retain my commission, with an assurance that he would endeavor, by all means, to give me a command." Later Washington did more than Hamilton himself had asked, when he gave him the leading of the storming party at Yorktown, a post envied by every officer in the army.

Apparently this generosity lessened Hamilton's resentment, for a correspondence on public affairs was maintained from this time on, though Madison stated long after "that Hamilton often spoke disparagingly of Washington's talents, particularly after the Revolution and at the first part of the presidentcy," and Benjamin Rush confirms this by a note to the effect that "Hamilton often spoke with contempt of General Washington. He said that ... his heart was a stone." The rumor of the ill feeling was turned to advantage by Hamilton's political opponents in 1787, and compelled the former to appeal to Washington to save him from the injury the story was doing. In response Washington wrote a letter intended for public use, in which he said,—

With the appointment as Secretary of the Treasury warmer feelings were developed. Hamilton became the President's most trusted official, and was tireless in the aid he gave his superior. Even after he left office he performed many services equivalent to official ones, for which Washington did "not know how to thank" him "sufficiently," and the President leaned on his judgment to an otherwise unexampled extent. This service produced affection and respect, and in 1792 Washington wrote from Mount Vernon, "We have learnt ... that you have some thoughts of taking a trip this way. I felt pleasure at hearing it, and hope it is unnecessary to add, that it would be considerably increased by seeing you under this roof; for you may be assured of the sincere and affectionate regard of yours, &c." and signed other letters "always and affectionately yours," or "very affectionately," while Hamilton reciprocated by sending "affectionate attachment."

On being appointed lieutenant-general in 1798, Washington at once sought the aid of Hamilton for the highest position under him, assuring the Secretary of War that "of the abilities and fitness of the gentleman you have named for a high command in the provisional army, I think as you do, and that his services ought to be secured at almost any price." To this the President, who hated Hamilton, objected, but Washington refused to take the command unless this wish was granted, and Adams had to give way. They stood in this relation when Washington died, and almost the last letter he penned was to this friend. On learning of the death, Hamilton wrote of "our beloved Commander-in-chief,"—