Justin is known for his abstract expressionistic style, often combing oil, enamel, and spray paint to create thick, layered works that are energetic and spontaneous. Recently he has been focusing on the human figure, incorporating faces and torsos, while still pushing rich brush strokes and automatic mark-making. The figures are ambiguous, often with no facial features or large marks covering their heads, yet Brennan is still able to capture a raw emotion that is evident through bold color choices and the immediacy of his application.