Leo Koenig was born to Jewish parents as Arye-Leyb Yaffe in the Selan' settlement near Babrujsk in the Russian Empire (currently Belarus) in 1889. In his formative years, he travelled extensively, studying in Jerusalem, Munich and Paris, finally settling in London in 1914, where he was closely associated with the Ben Uri Art Society, founded by Yiddish-speaking, orthodox Jewish migrants in 1915. A great supporter of Yiddish culture in exile and of the concept of 'Jewish art', during 1920 he produced and edited a short-lived but remarkable Yiddish art and literary journal entitled 'Renesans' [Renaissance], which boasted a stellar list of Jewish artist contributors.
Art critic and editor Leo Koenig was born Arye-Leyb Yaffe to Jewish parents on 12 January 1889, in the Selan' settlement near Babrujsk in the Minsk governorate of Russian Empire (now Belarus). He received his primary education in Odessa. In 1906 he moved to Jerusalem, where he studied with Samuel Hirszenberg at the Bezalel School of Art, founded earlier that year. During that period, he published his first short stories in Hebrew in Jerusalem. In order to remain in Palestine, he exchanged passports with a certain Leo Koenig from Łódź and kept this name for the rest of his life. In 1911 Koenig went to study in Europe, first attending the Academy of Fine Arts in Munich and later relocating to Paris, where he lived at the artists' commune, La Ruche. In Paris he became friends with fellow Russian immigrant, Marc Chagall, with the two keeping correspondence throughout their lives. As Benjamin Harshav has written, in 1910–1914, Koenig was promoting the notion of 'Jewish Art' and tried to dissuade Chagall from 'the avant-garde nonsense' (Harshav 2003, p. 219). While at La Ruche, Koenig became head of a group of young Jewish painters from Russia and Poland called Machmadim, which included Pinchus Krémègne, Isaac Lichtenstein, Henri Epstein, Marek Schwarz and Léon Indenbaum. In 1912, they produced a textless illustrated journal under the same title, which is considered to be one of the first Jewish art journals of the 20th century. During that period, Koenig also wrote extensively on Jewish art for the French Yiddish press, becoming one of the pioneers of Yiddish art criticism.
In 1914, Koenig moved to London and settled in Kensington, where he became associated with the Ben Uri Art Society, founded in 1915 by fellow émigré Lazar Berson, in London's Jewish East End Jewish ghetto. Towards the early 1920s, members of Ben Uri, which started as a predominantly Yiddish-speaking enterprise, began to develop close ties with a new generation of Anglo-Jewish artists and writers. The synthesis of the two groups produced a short-lived but remarkable Yiddish art and literary journal Renesans [Renaissance], of which six issues saw light under the overall editorship of Koenig. Renesans boasted a stellar list of contributors, among them the renowned Anglo-Jewish novelist, Israel Zangwill, painters David Bomberg, Jacob Kramer and Lucien Pissarro, and Yiddish writers Boruch Glassman, Melech Ravitch and Zishe Weiner. Notably, its January 1920 issue featured a review of Bomberg's iconoclastic exhibition held at the Adelphi Galleries, written by fellow 'Whitechapel Boy', Stephen Winsten [Samuel Weinstein]. The journal compared favourably with other avant-garde European Yiddish cultural magazines of the period published in Moscow, Kyiv, Warsaw, Łódź, Berlin and Paris. In June 1927, Koenig took part in the Fifth Congress of the International PEN Club as a representative for Yiddish literature.
In 1933 Koenig became part of the small executive of the newly founded Committee for Enlightenment on Jewish Affairs , whose aim was to ‘enlighten public opinion on the general position of the Jews in the world, and especially on the present crisis of the Jews in Germany […] Although Jews suffer special maltreatment and oppression, this committee is convinced that […] the Jews fight against this oppression is also a fight for the highest ideals in humanity’ (The Manchester Guardian 1933, p. 18). The Committee, whose honorary president was the Jewish scholar and rabbi, Moses Gaster (his portrait head by Elsa Fraenkel is in the Ben Uri Collection), also published a bulletin and a collection of essays on the condition of Jews in Germany. Koenig gathered Yiddish-speaking artists and writers around him, including I. A. Lisky and A. M. Kaizer – editor and writer, and secretary of the Federation of Jewish Relief, respectively – who often met at Koenig’s house on Hurstwood Road in north west London, for tea and discussions on art. In 1930 Koenig contributed an important essay on the status of Jewish artists in Britain, in both Yiddish and English, entitled Jews and Plastic Art, to Ben Uri's second catalogue, following its inaugural catalogue dating from 1925. During the 1930s and 1940s, Koenig continued publishing prolifically in both languages. Among his novels was A Week After Life (1934), describing the life of a typical Jewish family in London's East End. Koenig also contributed to the Jewish pictorial monthly New Life.
In 1954, Koenig immigrated to Haifa, Israel, where he continued to write essays in Hebrew and was a frequent contributor to the Israeli newspaper Davar. In 1966 his essay on Jews and Visual Arts featured in 1915-1965. Fifty Years of Achievement in the Arts. Commemorative Volume to Mark the Fiftieth Anniversary of the Foundation of the Ben Uri Art Society. Leo Koenig died on 29 August 1970 at Kibbutz Hatzerim near Beersheba, Israel. Leo Koenig's daughter, Ghisha Koenig (1921-1993), was a sculptor; one of her works, Compositors VI, is held in the Ben Uri Collection.