He taught at the San Francisco Art Institute (SFAI) for many years, where he held the title of associate professor.
A digital image of his murals was included in the 2017 Tate Modern exhibition Soul of a Nation: Art in the Age of Black Power in London.
[6][7] He was involved in Civil Rights activism and showed his work around the city, eventually meeting artist Emory Douglas of the Black Panther Party.
Seeking advice on a 1974 mural commissioned by the San Francisco Unified School District, a young Crumpler entered Elizabeth Catlett's tutelage, and his life was changed when she connected him with famed muralists José Clemente Orozco, and Pablo O’higgins.
[11] In 1936, Russian immigrant Victor Arnautoff was hired by the Works Progress Administration to paint a mural at George Washington High School in San Francisco.
To prepare for designing the mural, Crumpler traveled to around the country for research, which he was able to do due to his father working for Pan American World Airways.