Itshok-Leib (Leonid Osipovitsch) Pasternak was born into a Jewish family of a small hotel owner in Odessa on March 22 (on April 3), 1862. The family had five more children. In early childhood already he manifested love of drawing, though parents did not approve of this hobby initially.
 

From 1874 Osip combined his studies at the Odessa Drawing School and a grammar school. Upon finishing school he tried and failed to enter the Moscow School of Painting, Sculpture and Architecture. In 1881 he entered the Moscow University and studied at the medical faculty for two years. It did not prevent him from painting. In 1882 he attended the Moscow Art Studio of Yevgraf Sorokin. 
 

In 1883-86 he studied at the Law Department of the Novorossiysk University in Odessa and at the same time at the Munich Academy of Arts. He was tutored there by Ludwig von Richterich and Sandor Liezen-Mayer, and took etching lessons from Ivan Shishkin.
 

After his painting A Letter from Home was purchased by Pavel Tretyakov for the Tretyakov Gallery, the artist decided to move to Moscow, where he married the pianist Rosalia Kauffman (1868–1939) in 1889. The same year Leonid Pasternak founded his own drawing school in Moscow. 
 

He contributed for the theatrical and musical illustrated magazine Artist (1889–95; Moscow). Leonid Pasternak participated in annual exhibitions of the Itinerants and was a member of the World of Art (Mir Iskusstva) association.

Works by Leonid Pasternak stand out with exact psychological characteristic, precise composition, skillful interior, and peculiar light and aerial atmosphere, with the most important parts highlighted and the space around wrapped up in half-shade.
 

In 1894 he became a professor at the School of Painting, Sculpture and Architecture and taught there till 1921. In those years he became friends with Leo Tolstoy and Rainer Maria Rilke.
 

In 1917-1921 Leonid Pasternak created a series of portrait sketches of Vladimir Lenin and a sketch of the funeral of Yakov Sverdlov. In 1921 he went to Germany for treatment together with his wife and daughters. The family never returned to the USSR. In emigration Leonid Pasternak created portraits of Albert Einstein, Rainer Maria Rilke, and John Osborne. In 1924 he participated in the historical and ethnographic expedition to Palestine that was organized by Alexander Kogan.

In 1938 he left Germany for England. Leonid Pasternak died in Oxford on May 31, 1945. Rosalia Pasternak died earlier, in 1939.