Tragically, Furst committed suicide November 24, 1991. Furst had separated from his wife and began taking Halcion, a sleeping drug that had been banned in Britain due to its possible side effects of amnesia, paranoia and depression. His drinking also became more of a problem. He was about to check into a rehab in 1992, and told his friends he was going to the car to fetch his cigarettes and jumped off an eighth story parking deck.
In 1991 Furst was hired by DC Comics to create a architectural scheme for Gotham City in the comics. These designs, known now as Old Gotham, were penciled by Furst's longtime draftsman Nigel Phelps and used prominently until 1998.