Leonard Pennario was an American classical pianist and composer.
He was born in Buffalo, New York, and grew up in Los Angeles, attending Los Angeles High School remaining in L.A. for his entire career. He first came to notice when he performed Edvard Grieg's Piano Concerto at age 12, with the Dallas Symphony Orchestra. The scheduled performer had fallen ill, and Pennario's piano playing had come to the attention of the conductor Eugene Goossens, who recommended him as the soloist after being assured by Pennario that he knew the work. In fact, he had never seen the music or even heard it, but he learned it in a week.
He studied with Guy Maier, Olga Steeb, and Isabelle Vengerova and attended the University of Southern California, where he studied composition with Ernst Toch. World War II interrupted his career, and he served in the U.S. Army Air Forces in the China Burma India Theater, where his piano skills were soon realized and served well entertaining troops of the Air Transport Command operation known as "The Hump". He occasionally had to play around keys missing from the keyboards of the pianos at a couple of the more remote bases.