‘Schoenberg the Painter’ serves as a cultural history of the early evolution of Arnold Schoenberg’s as an artist. In particular, it explores how the personal relationship between the Austrian expressionist artist, Richard Gerstl (1883–1908) and Schoenberg became key in Schoenberg’s own artistic development. In particular, this chapter examines the paths that led to the convergence of the two men’s creative output in Gmunden in July 1908, which saw Schoenberg compose his seminal Second String Quartet, op.10, and become, in the vocal fourth movement, the first to cross the bridge to atonality, and saw Gerstl produce a series of extraordinary large-scale expressionist portraits of members of Schönberg’s circle. This chapter offers new hypotheses not only regarding the evolution of Schoenberg’s works over the period of the relationship between the two men, but also the previously under-considered level of influence that Gerstl may have had on Schoenberg’s wider creative and musical output at the time.