Greek conductor Dimitri Mitropoulos, who previously worked with Pennario, said the best-selling recording artist had the unique combination of both soul and talent, the Los Angeles Times reported Saturday.
"Playing with this musician has been one of the joys of my life," Mitropoulos said. "He has technique, but he has what is more important, a soul."
Music critic Andrew Porter was equally appreciative of the Pennario's accomplishments, which included becoming a permanent Van Cliburn International Piano Competition jury member.
"Pennario's playing knows no limit," Porter said of the pianist, who died Friday after a lengthy battle with Parkinson's disease. "The technique is magnificent and unshakable."
Pennario first burst onto the music scene when he was 12, performing with the Dallas Symphony and later went onto play with the New York Philharmonic and the Chicago Symphony.
The Times said he is survived by his brother, Dr. Joseph Pennario.