Siem was born on January 14, 1986, in London. His father, Kristian Siem, was a businessman, and he is a distant relative of 19th century touring violinist Ole Bull. Charlie Siem has three sisters, all artistically inclined. He took up the violin at age three after hearing Yehudi Menuhin play Beethoven's Violin Concerto in D major, Op. 61, on the radio and listening to his mother's classical cassettes. Siem was a child prodigy who was making concerto appearances by age 15. At 18, he performed with the Royal Philharmonic Orchestra. He attended Eton College and Girton College at Cambridge University, going on to the Guildhall School of Music and, finally, the Royal College of Music in London. His teachers included Itzhak Rashkovsky and Shlomo Mintz. Early in his career, Siem performed in pop concerts with such artists as Miley Cyrus, Boy George, and The Who, and singers Katy Perry and Lady Gaga proclaimed themselves fans. He appeared in the Italian men's fashion magazine L'Uomo Vogue. In 2008, he made his debut recording on the Challenge Classics label, performing sonatas by Elgar and Grieg with pianist Andrei Korobeinikov.
Siem has appeared with a variety of top orchestras in Britain and far beyond, including Norway's Bergen Philharmonic and Oslo Philharmonic, the London Symphony, and the Moscow Philharmonic. His festival credits include appearances at the Spoleto, St. Moritz, and Gstaad Festivals, among others. In 2011, Siem moved to the Warner Classics label and issued the album Charlie Siem Plays Virtuoso Violin Works. He released several more albums on Warner, including one devoted to the virtuoso concertos of Wieniawski, Bruch, and Bull. He moved to Signum Classics for the album Under the Stars in 2014. Siem returned in 2020 with an album of encores and the like, Between the Clouds. In 2022, he released an album featuring Beethoven's Violin Concerto, with the Philharmonia Orchestra, on Signum Classics. ~ James Manheim, Rovi