In the late 1930s to early 1940s, Philip Guston's work was deeply embedded in the Social Realism movement, which aimed to shine a light on the socio-economic conditions of the era, emphasizing themes of struggle, conflict, and the everyday lives of the working class. During this period, Guston, like many of his contemporaries, was influenced by the Mexican muralist movement, which often portrayed similar themes of social injustice and class struggle. His works from this time are characterized by their direct engagement with political and social issues, often depicting stark, powerful imagery meant to provoke thought and highlight inequalities.

One of the most significant aspects of Guston's involvement in Social Realism was his participation in mural projects under the Works Progress Administration (WPA), a key component of the New Deal aimed at providing work for artists among many others during the Great Depression. Through this, Guston painted murals that not only provided him with financial support during difficult times but also allowed him to contribute to the public's engagement with art that reflected social issues and ideals of communal effort and solidarity​ (The Art Story)​.

Guston's work during this period often incorporated blunt, powerful imagery, such as clenched fists and Klansmen, to call attention to social injustices. For instance, in 1932, Guston and fellow artists created a mural to support the Scottsboro Boys, nine Black teenagers falsely accused of sexual assault. This work exemplified Guston's commitment to using his art as a form of activism, bringing attention to critical issues of racial injustice and inequality​ (invaluable.com)​.

By the late 1940s, Guston began to shift towards Abstract Expressionism, moving away from the direct social commentary of his earlier works but still carrying forward a deep engagement with the human condition and the complexities of the modern world. This period of transition marks a significant phase in Guston's career, demonstrating his evolving approach to art and its relation to society​ (invaluable.com)​.

Philip Guston's contributions to Social Realism in the late 1930s and early 1940s reflect his deep commitment to addressing social issues through art. His works from this period stand as powerful statements against injustice, showcasing his belief in the potential of art to reflect and shape societal values and concerns.