Collins has written novels, screenplays, comic books, comic strips, trading cards, short stories, movie novelizations and historical fiction. He wrote the graphic novel Road to Perdition (which was developed into a film in 2002), created the comic book private eye Ms. Tree, and took over writing the Dick Tracy comic strip from creator Chester Gould. Collins briefly wrote the Batman comic book in 1987 and crafted a new origin for the Jason Todd character. Collins and artist Terry Beatty created Wild Dog at DC that same year in a self-titled limited series. The character later appeared as a feature in the Action Comics Weekly anthology. As of 2016, Wild Dog became a recurring character in the Arrow television series and is portrayed by actor Rick Gonzalez.