Gerle trained in Hungary, where he was raised, and performed in New York and London in the 1950s and '60s. He taught at the Peabody Institute in Baltimore, the Mannes College of Music in New York, and at the University of Maryland Baltimore County, where he started the orchestra program.
He was widely admired for his technique and his diverse repertoire. Harold C. Schonberg, a New York Times critic, wrote of a 1958 concert, "As a violinist pure and simple, Mr. Gerle has all the answers. He had some of the steadiest bow arms this listener has heard, and his intonation is flawless."
According to the Post, Gerle was discovered hiding in a music professor's apartment in Budapest in 1945. He was nearly shot as a suspected sniper by the Soviet soldiers who found him. Because he had his violin case with him, he was ordered to play a piece by Tchaikovsky. His performance convinced the Soviets that he was a musician rather than a sniper, and his life was spared.