Simon Laks was born in Warsaw on 1 November 1901. He was born a Russian citizen. He studied mathematics in Vilnius and Warsaw. In 1921, he entered the Conservatoire of Warsaw, the capital of the newly independent Poland. He became a Polish citizen. In 1924, the Warsaw Philharmonic played one of his works in public for the first time. It was the symphonic poem, Farys (now lost).
He left Poland for Vienna in 1926. He worked providing piano accompaniment for silent films. He then returned to Paris where he continued his musical studies until 1929 at the Conservatoire National. At that time, he spoke Polish, Russian, French, German, and English. He became one of the founder members of the Association for Young Polish Musicians in Paris, founded at the end of 1926 with his help. Many of Laks' works were written for Parisian concerts at this time: his Quintet for wind instruments (lost), his Second string quartet (lost) and his Sonata for cello and piano. In Paris, Simon Laks met Tadeusz Makowski. In the 1930s, he formed a fruitful artistic collaboration with the singer Tola Korian. He wrote songs for her in Polish and French, as well as many songs she had written herself.
Simon Laks composed neo-classical music. In 1941, being Jewish, was arrested by the German authorities and interned in the camp at Pithiviers, close to Orléans. He was deported to Auschwitz in July 1942. As a musician, he was treated better than most deportees, and survived for more than two years where he was the head of the orchestra at the concentration camp.
After the war, he recounted his experience in the book Mélodies d'Auschwitz. He also reflected on the role music had in the extermination. When he arrived in the camp, he noted: "…music stand, music stands! (…) Where there are music stands, there must be musicians. You can't have one without the other. Who plays music here? The executioner, or his victims? What type of music do they play? Danses macabres? Funeral songs? Hitlerian chants?" He said that at Auschwitz, the orchestra played twice a day, at the start, and at the end. The accompanied the Kommandos when they entered and exited the camp gates. He stated that far from being a medium of resistance, music was a supplementary torture instrument, an instrument of total domination. Music aggravated the detainees, physically and morally. It incited the detainees to work, without reflection. On 28 October 1944, he was transferred to Dachau. On 29 April 1945, the camp was liberated by the American army. On 18 May, he was returned to Paris and became a French citizen.
Simon Laks worked in the baroque and classical genres, the traditional principals and formal construction of instruments combining for tonal harmony. He possessed a sense of proportions, a mastry of polyphonic technique, a rhythmic purity, and a simple and pure style. The many songs of Simon Laks cover many influences: the vocal lyrical romantic tradition of Polish lieds and the French interwar style. From 1972, Simon Laks dedicated his writing to translation. He had a passion for linguistic problems, but also for social and political problems. He is the author of a number of books. He died, aged 82, in Paris.