Critics and peers acknowledge Mr. O’Neal as perhaps the leading exponent of mid-20th-century jazz piano technique. “He’s a very special cat,” said the pianist Barry Harris, a bebop luminary who mentored Mr. O’Neal in the 1970s and ’80s. “If ever somebody sounded like Art Tatum, it’s him. He’s got it all.”

The similarity wasn’t lost on the director Taylor Hackford, who cast him in the role of Tatum in the 2004 biopic “Ray.” In one scene Mr. O’Neal sits onstage at a club, flawlessly carrying off Tatum’s signature downhill sprints and herculean harmonic leaps.

The guitarist Kurt Rosenwinkel, 43, who has featured Mr. O’Neal as a guest performer at his concerts, considers him “an important figure” for younger players to hear. “My jaw dropped when I heard him play piano — and then my heart dropped when I heard him sing,” Mr. Rosenwinkel said.

Performing with Joe Farnsworth on drums and Yuriy Galkin on bass