The composer's father, Doctor Sibelius, took an interest in violin and guitar playing, and he liked to sing. Thus Janne Sibelius also learned the basics of piano playing at an early age and he started to pick out notes on the violin at almost the same time. Early in his life Janne also became interested in the instrument collection of his Uncle Pehr in Turku. The collection included several violins. His interest in the violin continued throughout his childhood.

Nevertheless, it was not until the autumn of 1881 that Janne, who was almost 16 years old, became the pupil of Gustaf Levander, the best violin teacher in Hämeenlinna. He made rapid progress, although his right arm was painful as a result of an accident. Due to an elbow fracture he would never be able to draw the bow of the violin to its full length.

Almost immediately after the lessons had started Janne was admitted to a newly-founded orchestra made up of Levander's pupils. He also started to play in a trio in which his brother Christian played the cello and his sister Linda the piano. From time to time his brother and sister also accompanied him in piano duets.

Chamber music became an important part of Janne's life. He played with the daughter of Theodor Tigerstedt, who was the municipal officer of health, and in 1882 he joined a string quartet in which Anna Tigestedt played first violin, Mr Levander the viola and the apothecary Elfsberg the cello. Their repertoire included quartets by Haydn. During the years 1882-1885, violin playing was Sibelius's most cherished pastime, and he also composed several chamber music works for his immediate circle.

In 1885 Sibelius passed his matriculation examination and moved to the Helsinki Music Institute. Mitroyan Wasilieff became his violin teacher and he demanded that Sibelius should practise four hours daily. That plan did not work out, but the teacher still regarded his pupil as a "musical genius". In his very first autumn Janne had to learn small-scale concertos by Viotti and Rode.

Sibelius advanced to second violin in the Institute's string quartet in the autumn of 1887, when Hermann Csillag became his teacher. Throughout his student years he also played actively in the Academic Orchestra under the guidance of Richard Faltin, the rehearsal master for the university.

As a soloist he at first received good reviews in the local newspapers, but gradually it became clear to everybody that Sibelius was more promising as a composer than as a violinist.

In 1887 Sibelius and his friends also founded a string quartet of their own. In addition to the composer and his brother Christian, the quartet was made up of Richard Faltin junior and Ernst Lindelöf. In a few years the boys managed to go through most of Haydn's string quartets and the first six quartets of Mozart and Beethoven.

One of Sibelius's music companions during these years of study was his composition teacher, Martin Wegelius, who was willing to accompany his pupil on the piano in his spare time. In addition, an important music companion for his future was Armas Järnefelt. He was accompanying Sibelius on the piano just at the moment when his sister, Aino, entered the room.

During his years of study in Berlin and Vienna Sibelius concentrated on his composition studies, but he also played the violin with his friends during chamber music evenings. In Vienna he was allowed to play as an extra violinist in the student orchestra, and in an attempt to improve his financial situation he even had an audition for the Vienna Philharmonic. However, the jury considered him too nervous to be an orchestral musician.

On returning to Finland, we know that Sibelius performed as a violinist on 21st August 1891, in Ekenäs, with the pianist Karl Ekman. On that occasion he played his Impromptu and Svendsen's Romance. In the same autumn he gave violin lessons to private students in Loviisa and continued to play chamber music. He also went to Helsinki to play in an orchestra when Robert Kajanus and Martin Wegelius – despite having been at loggerheads for long periods - united their strength in a festival concert.

In the autumn of 1892 he was engaged as a teacher at Martin Wegelius's Music Institute and at Kajanus's Orchestral School. He was teaching theory and violin playing, and sometimes he had over 30 hours of teaching in a week. In addition to the teaching Sibelius still played second violin in the quartet of the Music Institute from the autumn of 1892 to the spring of 1893

Sibelius stopped giving violin lessons quite soon, but at the request of Kajanus he came along to add strength to the violin section of the orchestra, at least until 1896.

Violin playing was useful for Sibelius, both as a composer and as a conductor. When the viola players tried to tease the young composer-conductor at the Heidelberg Music Festival in 1901, Sibelius calmly took the viola and showed how the part should be played. The attitude of the orchestra changed immediately.

Sibelius had dreamt of a career as a violin virtuoso, and in 1904 he gave vent to his frustration by writing a violin concerto whose original version is one of the most difficult of all violin works. Aino Sibelius described how her husband played while he was composing: "He stays awake all night, plays extremely beautifully, he cannot tear himself away from these delightful melodies - he has so many ideas that it is hard to believe it. And all the themes have so much potential, so much life."

The first public performance of the violin concerto was not entirely successful, and the composer revised the work in 1905 so that it became slightly easier and better balanced.

After the move to Ainola Sibelius mainly played the violin at home. "Sometimes, actually quite often, we play Mozart's and Beethoven's violin sonatas together. It is such fun," Aino Sibelius said at the time when Sibelius was writing Pohjola's Daughter.

Among Sibelius's daughters, Eva, Ruth, Katarina and Heidi learned to play the piano. Only Margareta played the violin and the viola like her father. The composer had two violins at his disposal, the better of which later came into the possession of Margareta's daughter Satu.

The composer eventually had to stop playing the violin because of the tremor in his hands, which became worse in the 1930s – indeed so bad that it impaired his writing. "I used to play the violin," he explained to one visitor. "I don't play anymore, but my fingers don't know it. They are still playing. A tremolo, you know, all the time."

The violin continued to be a natural part of Sibelius's role as a musician until the very last years of his life.

"When he was sitting in the armchair in the library at Ainola, his left hand very often fingered the imaginary neck of a fiddle, using his right forearm as the neck," the composer's son-in-law Jussi Jalas wrote in his memoirs. "His hand shifted into positions, his fingers made as if to produce double-stops, and tried to form themselves into fingerings for melodic lines, which in his mind actually sounded like a violin playing."