Jean Sibelius has been played on NTS over 20 times, featured on 20 episodes and was first played on 31 May 2017.

Jean Sibelius (8 December 1865 – 20 September 1957) was a Finnish composer of the late Romantic and early modern periods. He is widely regarded as Finland's greatest composer, and his music is often credited with contributing to the development of a stronger national identity during a time when the country faced efforts at Russification in the late 19th century.

Sibelius’s core works include seven symphonies, which, along with his other major compositions, are frequently performed and recorded both in Finland and internationally. His best-known pieces include "Finlandia," the "Karelia Suite," "Valse triste," the Violin Concerto, the choral symphony "Kullervo," and "The Swan of Tuonela" from the "Lemminkäinen Suite." His output also includes works inspired by nature, Nordic mythology, and the Finnish national epic, the Kalevala; over one hundred songs for voice and piano; incidental music for numerous plays; the one-act opera "The Maiden in the Tower"; chamber music; piano music; Masonic ritual music; and 21 publications of choral music.

Sibelius composed actively until the mid-1920s. After completing his Seventh Symphony (1924), the incidental music for "The Tempest" (1926), and the tone poem "Tapiola" (1926), he ceased producing major new works for the remaining three decades of his life—a period often called the "silence of Järvenpää," named after his home. Although he is thought to have stopped composing, he made attempts to continue, including incomplete work on an eighth symphony. In his later years, he focused on writing Masonic music and revising earlier compositions, while maintaining an interest in contemporary musical developments, though not always favourably. Sibelius expressed that he felt he had written enough.

His image appeared on the Finnish 100 mark note until the adoption of the euro in 2002. Since 2011, Finland has celebrated a flag flying day on 8 December, Sibelius’s birthday, known as the Day of Finnish Music. In 2015, the 150th anniversary of his birth was marked by special concerts and events, especially in Helsinki.