He was Irish, but with neither the proverbial charm nor the luck. Generals are not much known for the former quality, but the latter, as Napoleon suggested, is one no successful commander can be without. And John Sullivan was an officer whom luck simply passed by.
Surveying his military career, one gets the impression that he was perpetually in motion but going nowhere, that he had virtually nothing to show for all his ambition and energy and combativeness, and that in the end nearly everything he did was counterproductive. It would not be so bad if he had been a likable fellow, but he was not; one senses that he was, by and large, singularly unattractive—always the glad-hander, a politician in or out of uniform, forever overconfident of success on the eve of battle, cocksure that he could do anything that was asked of him and more—and in the wake of events defending himself against the inevitable criticism, endlessly carping and whining about what had gone wrong and laying the blame on someone else or on some mysterious force that was beyond his control.