Musin began playing piano at the urge of his father, a Jewish watchmaker and enrolled in the [url=https://discogs.com/label/1513139]Petrograd Conservatory[/url] in 1919. Subsequently, he decided to pursue conducting instead and joined Nicolai Malko and Alexander Gauk classes in 1925. Ilya became Fritz Stiedry's assistant at the Leningrad Philharmonic Orchestra in 1934. Musin was appointed to lead the National Philharmonic Orchestra Of Belarus in Minsk but barely had any career advancements due to his refusal to join the Communist Party.

In 1932, Ilya Musin returned from Belarus and began teaching at the [url=https://discogs.com/label/1513139]Leningrad Conservatory[/url]. He developed a comprehensive theoretical system to enable the student to communicate with the orchestra with the hands, requiring minimal verbal instruction. It was one of the most thorough and detailed systems of conducting gestures, and Ilya Musin eventually published The Technique of Conducting manual. From 1941 to '45, Ilya Musin stayed in Tashkent, Uzbekistan, where he gave one of his most notable conducting performances. On 22 June 1942, exactly one year after the Nazi invasion, Musin conducted Dmitri Shostakovich's Symphony No. 7, Op. 60 (Leningrad Symphony) — the second-ever life rendition.

In 1994, Musin gave masterclasses at the Royal Academy of Music in London, UK.

Notable students
Rudolf Barshai
Semyon Bychkov
Tugan Sokhiev
Oleg Caetani
Vassily Sinaisky
[a=Konstantin Simeonov]
Odysseas Dimitriadis
[url=https://discogs.com/artist/1894544]Vladislav Chernushenko[/url]
Viktor Fedotov
Arnold Katz
[url=https://discogs.com/artist/1762492]Andrei Chistyakov[/url]
Siân Edwards
Martyn Brabbins
Peter Jermihov
Alexander Walker
Yuri Temirkanov
Valery Gergiev
Teodor Currentzis
Leonid Korchmar
Oleg Proskurnya, who was Musin's assistant for the "International Conducting Workshop" and founded the Advanced Conducting Academy to continue his work.