Mark Grotjahn's "Untitled (Captain America)" series is a remarkable body of work that combines the comic book hero's symbolism with abstract expressionism. Created between 2008 and 2009, this series consists of large-scale, ten-part drawings rendered in colored pencil and oil on paper. The works were first exhibited at the Kaikai Kiki Gallery in Tokyo in 2010 and later showcased at Gagosian Gallery in New York in 2016.

The series utilizes Captain America's iconic red, white, and blue color scheme to create vibrant, dynamic compositions. These pieces feature Grotjahn's signature centrifugal radiant motif, which synthesizes the character of Captain America into pure, vibrating lines of force. The geometry and process resonate with each other through razor-sharp perspectival rays and random marks, reflecting Grotjahn's meticulous working method. Acid-yellow calligraphy surfaces intermittently, adding an abstract expressionist layer to the pieces (Gagosian).

Grotjahn's work often reflects on the impact of 20th-century capitalism on art, aligning with the tradition of artists like Andy Warhol and Jasper Johns, who explored themes of consumerism and pop culture. His "Sign Exchange" project (1993-98), where he replicated and swapped store signs, echoes this blend of high and low art, a theme that continues in the "Untitled (Captain America)" series (Gagosian) (Artmap).

The "Untitled (Captain America)" series stands out for its monumental scale and the energy it brings to the gallery space. Grotjahn's use of geometric abstraction and symbolic color creates a visually striking homage to the comic book hero, while also engaging with broader themes of American identity and artistic tradition (Gagosian Shop).