Kahn was born in Mannheim, the second son of Bernhard Kahn^[1] and Emma Eberstadt. One of his seven siblings was the wealthy financier Otto Kahn whose son Roger Wolfe Kahn was a successful jazz musician, composer and aviator. His parents belonged to a distinguished German-Jewish family of bankers and merchants. In 1882, Kahn entered the Königlichen Hochschule für Musik in Berlin, where he studied for the next three years. Between 1885 and 1886, he continued his musical education under Josef Rheinberger in Munich. On a visit to Vienna the following year, Kahn met and befriended composer Johannes Brahms, who offered to make Kahn his pupil.^[2] Although Kahn declined the invitation out of diffidence, Brahms's music would exert a profound influence on his compositional style throughout his career.^[3]

After finishing his military service, Kahn worked as a freelance composer in Berlin until 1890. For the next three years he was employed as a Korrepetitor (rehearsal pianist) at the Stadttheater in Leipzig. Having been appointed lecturer in composition at his alma mater in 1894, Kahn went on to train some of the best-known musicians of the 20th century. His students include the pianists Arthur Rubinstein and Wilhelm Kempff, the conductor Ferdinand Leitner, the composers Theodore Holland, Nikos Skalkottas and Günter Raphael, and the violinist Karl Klinger.

While Kahn was composing and teaching in Berlin he also was active as chamber musician and Lied accompanist in concert with leading soloists and singers of his time, ranging from Joseph Joachim and Richard Mühlfeld to Adolf Busch, from Johann Messchaert to Ilona Durigo and Emmy Destinn.

In 1916, Kahn was elected to the Prussian Academy of Arts, a membership he held until 1934 when the Nazi regime ordered him to resign because he was Jewish. The Nazis also prohibited the publication and performance of his music. This drove him, at the age of 73, to leave Germany for England in 1939 with his wife Katharina, where (as with many émigré musicians of the period) he spent the last years of his life in relative obscurity but composing prolifically. He lived in Ashtead, Surrey and in Biddenden, Kent, where he died. Kahn and his music were almost entirely forgotten after World War II, but are being rediscovered by musicians and audiences, as is the case of many other composers of "degenerate music" persecuted by the Nazis.^[4]

Kahn composed a vast quantity of chamber music, writing in an intimate, lyrical style that is reminiscent of Felix Mendelssohn, Robert Schumann, and Brahms. He was also an admirer of Reger. But aside from the Serenade Aus der Jugendzeit ("From Youth") and the Konzertstück, Op. 74 for piano and orchestra in E-flat minor, he mostly avoided the large scale orchestral forms and emotional extravagance of late Romanticism. There are a number of ambitious works for chorus and orchestra, such as the Goethe setting Mahomets Gesang, Op. 24 (1896), the Sturmlied, Op. 53 for chorus, orchestra and organ (1910), and the Festgesang, Op. 64 for the same forces.^[5]

Of the chamber music there are three violin sonatas,^[6] two cello sonatas, four piano trios,^[7] two string quartets, three piano quartets and two piano quintets. Particularly notable are the Violin Sonata in E, Op. 50 (1907), the Piano Quartets, Op. 30 (1899) and Op. 41 (1904), and the String Quartet in A minor, Op. 60 (1914). The unconventionally scored Quintet in C minor of 1911 (for piano, violin, cello, clarinet and horn, the same combination used by Vaughan Williams in 1897), has been recorded.^[8] Lieder were also very important to Kahn: he composed around 180 solo songs and 13 duets.^[5]

Kahn was often commissioned to create works for some of the finest musicians of the early decades of the 20th century up to the young Adolf Busch, with whom Kahn gave the first performance of his Suite, Op. 69 for violin and piano in 1920. His first Violin Sonata in G minor (1886) was dedicated to Joseph Joachim, who asked to perform it when Kahn was still a young student in Berlin. Clara Schumann mentioned this sonata in her diary. The second Violin Sonata, in A minor, Op. 26 (1897) was dedicated to Joachim, while the String Quartet No. 1 in A major, Op. 8 (1889) was dedicated to and first performed by the Joachim Quartet. The second string quartet was premiered by the Klingler Quartet, successor of the Joachim. His Clarinet Trio, Op. 45 was dedicated to and performed by the famous clarinetist Richard Mühlfeld who also inspired Brahms's late chamber compositions. Hans von Bülow conducted the Berlin Philharmonic Orchestra in the world première of Kahn's orchestral serenade in 1890.

His renewed compositional activity after leaving Germany in 1938 resulted in a large collection of piano music, including more than 1,100 pieces. These took the form of a musical diary, the Tagebuch in Tönen, begun in 1935, with Kahn writing several short piano works per week until his death in 1951.^[4] Apart from an extracted set of 29, these only exist in manuscript at the Akademie der Künste in Berlin. The pianist Maksim Štšura has recorded a selection,^[9] as has Danny Driver.^[10]

• Adrift: includes Trio Serenade, op. 73. Delphine Trio, TRPTK TTK0113 (2024) and Ensemble Schumann, MSR (2014)
• Cello Sonatas: No. 1, op. 37 (1903) and No. 2, op. 56 (1911), Three Pieces, op. 25 (1897). Torleif Thedéen (violoncello) & Oliver Triendl (piano), CPO 555139-2 (2019)
• Chamber Music: Piano Trio No. 4 in E minor, op 72 (1922), Serenade in F minor, op 73, Piano Quintet in D major (1926). Hohenstaufen Ensemble, Hänssler Classic HC22075 (2023)
• Clarinet Trios: Includes Clarinet Trio, op. 45 (1906). Trio Bornalie, HERA 02113 (2005)
• Complete Piano Trios: No. 1 in E major, op. 19 (1893), No. 2 in E flat major, op. 33 (1900), No. 3 in C minor, op. 35 (1902), No. 4 in E minor, op. 72 (1914). Hyperion Trio, CPO 777 791-2 (2014)
• Kahn Piano Trios: No. 1 and No. 2. Max Brod Trio, MDG 90319406 (2016)
• Robert Kahn: Piano Quartet No. 2 (1899), Serenade for String Trio (1933). Hohenstaufen Ensemble, Hänssler Classic HC98010 (2013)
• Leaves from the Tree of Life: Lieder selection and excepts from Tagebuch in Tönen. Ensemble Emigré, Rubicon Classics RCD1040 (2021)
• Works for Violin and Piano: Violin Sonata No. 1 in G minor, op. 5 (1886), Violin Sonata No. 2 in A minor, op. 26, Violin Sonata No. 3 in E Major (1907), op. 50, 5 Tonbilder, op. 36, 2 Violinstücke, op. 4, Suite in D Minor, op. 69. Elina Vahala (violin) & Oliver Triendl (piano). CPO 777785-2 (2016)

• List of émigré composers in Britain

• Website about life and Music of Robert Kahn
• LexM Article (in german): Robert Kahn (by Steffen Fahl 2009)
• Lyrics of selected songs
• Robert Kahn's Chamber Music Soundbites and discussion of several works
• Tagebuch in Tönen No. 53, performed by Maksim Štšura, piano
• Free scores by Robert Kahn (composer) at the International Music Score Library Project (IMSLP)