Leonard Pennario was among the most popular American-born concert pianists of the twentieth century. Pennario's professional career began at the tender age of 12 when he filled in for an ailing soloist on the Grieg Concerto in A minor at a 1936 concert with the Dallas Symphony Orchestra. Freshly inducted into the U.S. Army, Pennario gave his Carnegie Hall debut in the uniform of an Army private, playing the Liszt Piano Concerto No. 1 in November 1943. Pennario returned from his tour of duty to an eager reception in the concert world. At the time, a Minneapolis critic wrote "Pennario is endowed with temperament, interpretive imagination and the capacity to express it, above and beyond the flyingest ten fingers you ever saw. He made the concert one of the most exciting and exhilarating musical experiences in a long, long time." This sentiment would be repeated in city after city as Pennario dutifully traversed the concert circuit.
Where many young concert artists view resettling in New York as a necessity, Pennario stayed based in Los Angeles his entire career. Although he gave his first European tour in 1952, Pennario concentrated his performances mostly within the continental U.S. and Hawaii. His choice of venue allowed him to build up longstanding relationships of value with other Los Angeles-based individuals and concerns, such as his friendship with composer Miklós Rózsa, who composed both a Piano Concerto and the outstanding Piano Sonata (1948) for him. Pennario also began an association with Hollywood-based Capitol Records, for whom he recorded for more than three decades. Among more than 60 albums made for Capitol is Pennario's recording of George Gershwin's Rhapsody in Blue with the Hollywood Bowl Orchestra under Felix Slatkin, one of the best-selling classical albums from the era of vinyl records.
When the classical division of Capitol went belly up in the early 1980s, it derailed Pennario's recording career, but it did not affect his standing in the concert world. In 1987 Pennario played a concert at Lincoln Center that was broadcast over PBS in observance of the 50th anniversary of Gershwin's death. Ultimately, by the 1990s, Pennario finally began to retreat from the concert stage, pursuing instead his other great ability — as a champion bridge player. Leonard Pennario was a great all-around pianist with an innate sense of musicianship — as one of his record producers put it "Pennario is one of those artists who just 'gets' the music."