ON a recent Sunday night at Smalls, the Greenwich Village basement club, Johnny O’Neal sat at the piano drawing lush clumps of harmony from the keys as he shouted a blues standard. “She puts whiskey in her coffee, whiskey in her tea,” he sang, his voice craggy and windblown. “Whiskey in her whiskey, too much whiskey for me.”

At one point his singing crumbled into a wheeze, and the crowd tittered, half sure it was all some put-on. “Y’all think I’m messing around, but that’s just my voice,” he said. “I’m hoarse.” The next line came out in a rasp too, and the audience laughed again — this time in complete solidarity.

Leaving one of Mr. O’Neal’s shows, you’ll probably feel both exhausted and unburdened. In conversation he likes to say, “I don’t play to get house.” But this is guile; his performances are a constant pursuit of affirmation. Between songs he tends to gush, “We just love you so much, you’re a lovely audience,” inviting an equal response.

Mr. O’Neal made a name for himself in New York in the early 1980s, drawing comparisons to classic jazz pianists like Art Tatum and Oscar Peterson. But after being mugged outside his Harlem apartment in 1986, he left New York and spent the next two decades performing in relative obscurity, eventually developing AIDS. He returned to New York four years ago, hoping to make good on his earlier promise, and as his health improves, he is quietly trying to put his career back on track.