"[5] Hannigan found it too difficult to both write and draw the series, so by the end of the story arc he was working solely as writer.
[5] As the artist on The Spectacular Spider-Man, Hannigan and writer Bill Mantlo co-created the characters Cloak and Dagger,[6] who appeared in a live-action television series on Freeform.
[8][9] He pencilled the covers on Batman in a lengthy run that spanned the majority of 1983–1985 with Don Newton providing the interior art.
[4] Hannigan and writer Mike Grell launched the first Green Arrow ongoing series in February 1988.
[10] The Batman: Legends of the Dark Knight series began in November 1989 with the five-part "Shaman" storyline by Hannigan and writer Dennis O'Neil.