Duffy has four cartoon collections published by Andrews and McMeel: Meet the Fusco Brothers!, Newark and Reality...Together Again, Cruel and Unusual, and Virtual Banality. The funniest thing to come out of New Jersey since Frank Sinatra, The Fusco Brothers have earned a loyal fan following in newspapers across America. The strip has been nationally syndicated since 1989.
In addition to creating The Fusco Brothers, Duffy produces cartoons that appear regularly in The New Yorker and other publications.