Leopold Pilichowski was born in Poland in 1866, the son of a poor Jewish farmer. He was taught to draw by the painter Samuel Hirszenberg (to whom he was distantly related), and studied in Munich and Paris, holding his first exhibition in Łódź in 1894. Around 1895 he began to address Jewish themes in his work, particularly the poverty of Jews in the cities. This commitment to social commentary led him to depict Jewish immigrants, wanderers and pedlars. In 1904 he moved to Paris and studied with Benjamin Constant, exhibiting there, as well as in London, New York and Warsaw; he later received the Legion of Honour from the French government. In 1906 his work was included in an exhibition of works by Jewish artists in Cracow and in 1907 he helped to co-organise an exhibition of Jewish Artists at the Gallery for Ancient and Modern Art in Berlin including his own work on the subject of exile. From 1908 Pilichowski was an active Zionist and probably his most famous portrait is one of the Zionist leader Theodor Herzl, painted in the same year and which exists in at least two versions (one in the Central Zionist Archives, Jerusalem; another in the Ben Uri collection).
A decade later, in 1914, at the age of 45, he moved to London, with his wife (the artist Lena Pillico) and their children, aided by Hebrew writer David Frishman. He travelled frequently between Paris and Łódź in 1914 and upon his return to London, concentrated on painting the impoverished Jews of Whitechapel. He lectured at the Ben Uri Art Society in 1916, and, again, in 1921, becoming Hon. President in 1926 - a position he held until 1933. In 1927, reflecting on a visit to Palestine two years previously, he lectured at Ben Uri on 'Palestine As Seen By An Artist', describing the close connection of the Jewish soul and spirit to the holy city of Jerusalem. He also served as president of the Association of Polish Jews in London. An 'Exhibition of portraits, landscapes, Jewish life studies, &c. by Leopold Pilichowski' was held at the Goupil Gallery, London in 1924 and he also participated (as did his wife, Lena Pillico) in the important survey exhibition 'Jewish Art and Antiquities' at the Whitechapel Art Gallery in 1927. In 1928 husband and wife were both also among the 16 artists who exhibited work at the Brooklyn Museum exhibition of 'Paintings, Sculpture and Drawings by American and European Artists' with Pilichowski showing 17 paintings (including a portrait of British Conservative politician Lord Balfour, architect of the 'Balfour declaration') to 29 by Pillico. In 'The Catalogue and Survey of Activities', published by the Jewish Art and Literary Society Ben-Uri in 1930, it was recorded that 'Mr. Pilichowski is one of the most popular Jewish painters of the older generation, and is at the present time, the President of the Ben Uri. Mr. Pilichowski, as already alluded to, has been of great assistance to the Society by reason of his expert advice and lectures on Jewish art which always attract large and eager audiences'. The minutes for 1931 refer to his donation of 30 pictures, at a nominal charge, including those by Josef Israels, Leopold Gottlib, Hermann Struck and Leon Hirszenberg.
Pilichowski died in London in 1934. His work is in collections including the National Museums of Crakow and Warsaw, the City Museum of Łódź, and the Jewish Museum, New York.