For more than 40 years, Boxer stood at the top rank of American Contemporary Artists. He has an international reputation and his art was shown widely during his lifetime and continues to be shown after his death in 2000. His work is included in the permanent collections of many museums, including MOMA, The Guggenheim Museum, the Whitney and others. He is a recipient of the Guggenheim and the NEA Awards and was a member of the National Academy of Design.

He was a prolific artist and produced much work during his lifetime. He liked working in different mediums and always thought that one nourished and influenced the other and were all connected. He made paintings, sculpture in marble and wood, sculpture constructions, works on paper, drawings, watercolors, works in pen and ink, prints and monotypes.