Clara Haskil was born into a Sephardic Jewish family in Bucharest, and began her career as a child prodigy. She entered at the Bucharest Conservatory when she was 6. At age 7 she was sent to Vienna and profited from the tutelage of Richard Robert (whose memorable pupils included Rudolf Serkin and George Szell) and briefly with Ferruccio Busoni. She was only 10 when she made her public debut there. At 10 she was sent to Paris to continue her training with Morpain, and, at 12, entered the Paris Conservatoire, officially to study at Alfred Cortot's class, although most of her tuition came from Lazare Lévy and Mme Giraud-Letarse. In 1909 she took the 1st prize at the Concours de l'Union Française de la Jeunesse of Paris, and also 2nd Prix at the Conservatoire. She graduated in 1910, age 15, with the Prémier Prix at the Conservatoire. She also graduated with a Premier Prix in violin.
Upon graduating, Haskil began to tour Europe, though her career was cut short by one of the numerous physical ailments she suffered throughout her life. In 1913 she was fitted with a plaster cast in an attempt to halt the progression of scoliosis. She did recover, making her New York debut in 1924 and her London debut in 1926. Frequent illnesses, combined with extreme stage fright that appeared in 1920, kept her from critical or financial success. Most of her life was spent in abject poverty. With the outbreak of World War II, Clara Haskil was trapped in occupied Paris, but was able to escape to Marseilles. There she survived a surreptitious surgical procedure to remove a tumor from her optic nerve. In 1942 she sought refuge in Switzerland, smuggled to Vevey, where she settled for the rest of her days. In 1949 she became a naturalized Swiss citizen. It was not until after World War II, during a series of concerts in the Netherlands in 1949, that she began to win acclaim.
As a pianist, her playing was marked by a purity of tone and phrasing that may have come from her skill as a violinist. Transparency and sensitive inspiration were other hallmarks of her style. Well regarded as a chamber musician, Haskil collaborated with such famed musicians as George Enescu, Eugène Ysaÿe, Pablo Casals, Isaac Stern and Arthur Grumiaux, with whom she played her last concert. While renowned primarily as a violinist, Grumiaux was also a fine pianist, and he and Haskil would sometimes swap instruments. She played as a soloist under the baton of such conductors as Ansermet, Barbirolli, Beecham, Celibidache, Karajan, Kempe, Klemperer, Kubelík, Markevitch, Münch, Sawallisch, Solti, Stokowski, Szell, among many others.
Haskil died from injuries received through a fall at a Brussels train station. She was to play a concert with Arthur Grumiaux the following day. An esteemed friend of Haskil, Charles Chaplin, described in 1961 her talent by saying "In my lifetime I have met three geniuses; Professor Einstein, Winston Churchill, and Clara Haskil. I am not a trained musician but I can only say that her touch was exquisite, her expression wonderful, and her technique extraordinary". (Internet infos compilation)