Popper was born in Prague, and studied music at the Prague Conservatory. He studied the cello under Julius Goltermann (1825–1876), and soon attracted attention. He made his first tour in 1863; in Germany he was praised by Hans von Bülow, son-in-law of Franz Liszt, who recommended him as Chamber Virtuoso in the court of Prince von Hohenzollern-Hechingen in Löwenberg. In 1864, he premiered Robert Volkmann's Cello Concerto in A minor, Op. 33, with Hans von Bülow conducting the Berlin Philharmonic. He lost this job a couple of years later due to the prince's death.