Hamilton was invited to become an aide to William Alexander, Lord Stirling, and another general, perhaps Nathanael Greene or Alexander McDougall.^[58] He declined these invitations, believing his best chance for improving his station in life was glory on the battlefield. Hamilton eventually received an invitation he felt he could not refuse: to serve as Washington's aide, with the rank of lieutenant colonel.^[59] Washington believed that "Aides de camp are persons in whom entire confidence must be placed and it requires men of abilities to execute the duties with propriety and dispatch."^[60]

Hamilton served four years as Washington's chief staff aide. He handled letters to Congress, state governors, and the most powerful generals of the Continental Army; he drafted many of Washington's orders and letters at the latter's direction; he eventually issued orders from Washington over Hamilton's own signature.^[61] Hamilton was involved in a wide variety of high-level duties, including intelligence, diplomacy, and negotiation with senior army officers as Washington's emissary.^[62][63]

During the war, Hamilton became the close friend of several fellow officers. His letters to the Marquis de Lafayette^[64] and to John Laurens, employing the sentimental literary conventions of the late eighteenth century and alluding to Greek history and mythology,^[65] have been read by Jonathan Ned Katz as revelatory of a homosocial or even homosexual relationship.^[66] Biographer Gregory D. Massey amongst others, by contrast, dismisses all such speculation as unsubstantiated, describing their friendship as purely platonic camaraderie instead and placing their correspondence in the context of the flowery diction of the time.