Like most composers, Tchaikovsky's musical talent was evident from an early age. Despite his special gifts, however, his parents had decided he was to pursue a career in law. So, at the tender age of ten, Tchaikovsky was sent off to the School of Jurisprudence in St. Petersburg. By the time he was nineteen, he had a job in the Ministry of Justice. Tchaikovsky had never abandoned his music, however, and in 1863 (after four years at the Ministry), he left law and enrolled at the Conservatory.

Tchaikovsky's teacher at the St. Petersburg Conservatory was the acclaimed pianist and composer Anton Rubinstein. Several years later, Anton's brother Nicolai established a new Conservatory in Moscow, and Tchaikovsky was invited on to the faculty. In Moscow, Tchaikovsky came into contact with a group of composers (including Rimsky-Korsakov and Balakirev) who were committed to infusing a true Russian essence into their music. Although Tchaikovsky was influenced by their ideas, and all of his music has a recognizable Russian flavor, he generally remained closer in spirit to his European counterparts.

Some of Tchaikovsky's most popular works, such as the Fantasy-Overture Romeo and Juliet (1870) and the First Piano Concerto (1875) were written early in his musical career. His ability to compose arching, passionate melodies was apparently a natural part of his genius. Composing was not always easy for Tchaikovsky, however. His struggle to compose his First Symphony (Winter Dreams, 1866) resulted in a nervous breakdown. He struggled against his sexuality, as well, marrying a woman he hardly knew in an attempt to "cure" his homosexual orientation. The marriage was a disaster and sent Tchaikovsky into a period of suicidal depression.

During this period of intense unhappiness, Tchaikovsky was rescued by the generosity of a stranger. Madame von Meck was a wealthy woman who had become enamored of Tchaikovsky's music. She supported him for fourteen years, during which time they never met, although they corresponded regularly. Tchaikovsky composed some of his most popular music thanks to her support, including the Fourth and Fifth Symphonies, the Violin Concerto, and the opera Eugene Onegin. In 1890, Madame von Meck withdrew her support, but Tchaikovsky's success was widespread by this time and he no longer needed financial assistance.

The music from his last years is his finest and most daring. The ballet The Nutcracker (1892) shows Tchaikovsky's mastery of the orchestra, creating magical effects by experimenting with unusual instruments and instrumental combinations. In the Sixth Symphony (the Pathetique, 1893), he created a new symphonic structure, beginning and ending with two slow and intensely lyrical movements; it is arguably the most profound and moving of his works.

Tchaikovsky's death has become a matter of musicological debate in recent years. It had been believed that the composer contracted cholera by drinking unboiled water. But in the 1970s, a Russian scholar found evidence that Tchaikovsky had been caught in a liaison with the nephew of a prominent official. According to this theory, the composer was then secretly tried by a private court that decreed he should commit suicide. Since homosexual activity was punishable by death in Russia, this account has plausability, but the real truth will probably never be known.