Naegele was born in Stuttgart in January 1928. In 1939 he traveled on the Kindertransport to England to escape Hitler's regime and in 1940 he was reunited with his parents in New York in the United States.
Though Naegele began his studies privately he was admitted to the High School of Music and Art, then on to Queens College and completed a doctorate in musicology at Princeton University. He also received a Fulbright Scholarship, allowing him to study at the Vienna Academy of Music under Franz Samohyl.
He was known for his involvement with the Marlboro Music Festival, which he had performed at since its inception. At Marlboro College he was under the tutelage of Adolf Busch, who he called his "idol".
- "Longtime member of Marlboro Music Fest dies at 83". Brattleboro Reformer. Vermont. February 8, 2011.
- Potter, Jon (December 29, 2011). "2011: The Year in Arts". Brattleboro Reformer. Vermont.
- Stearns, David Patrick (August 6, 2000). "Where Musicians Go to Grow at the Storied Marlboro Music Festival in Vermont, Classical Performers of all Ages are Given a Precious Gift: Time to Explore Their Art". The Philadelphia Inquirer. pp. I01.