Born in 1803 near Lyon, France, at the age of 18 he went to Paris originally to study medicine, but eventually abandoned this to pursue a career in music. In 1826 he began attending the Conservatoire and produced a number of compositions which were not performed. In the late 1827 he saw the actress Harriet Smithson in Shakespeare's Hamlet and Romeo and Juliet. He became infatuated with her and she later became his wife. Also in the late 1820's, he attended concerts of Beethoven's music and read Goethe. All of these things were to prove to be important influences in his artistic development.
In 1830 he wrote his most famous piece, the Symphonie Fantastique, the seminal piece of the Romantic period, a masterpiece of orchestration and drama. It was subtitled 'Episodes in the life of an artist' and was about his love affair with Smithson.
After winning the Prix de Rome, he travelled to Italy.
After returning to France in 1834, he composed the piece for viola and orchestra called Harold in Italy, which was inspired by Byon. Paganini had commissioned the work, but although he apparently liked it he never played it as it is not a conventional concerto.
His operas Benvenuto Cellini, La Damnation de Faust and Les Troyens were not successful in France, but were better received abroad. Berlioz also worked as a guest conductor, and he toured in England, Germany and Russia. To earn extra income, he also contributed to musical criticism, and championed the works of other Romantic composers like Liszt and Schumann.
He was made an Officier de la Légion d'honneur in 1864 and died in Paris in 1869.
To sum up, he was one of the great Romantics, successfully integrating the literary ideas of the times into his works. He also revolutionised the use of the orchestra, influencing composers like Wagner and Berlioz's friend Liszt. His use of the idee fixe in numerous works was a precursor to the use by Wagner of the leitmotif. Ironically, he was not a great pianist, and was only competent at the guitar and flute. His music continued to be largely neglected until the 1950's and 60's, when conductors like Rafael Kubelik, Charles Munch and Sir Colin Davis began including it on their concert programs.
Today, we are fortunate to have many fine recordings of his works widely available. The large forces which some of his stage works require still prohibit regular performance, but his orchestral works have become a firm part of the regular repertoire.