All of the wide shots of the actors on the ledge were real. Restraining cables were either hidden from camera view or edited out in post-production.
Sam Worthington helped kick start Man on a Ledge into production when he expressed early interest in the script. Worthington partially admits to being intrigued by the role because of his fear of heights, and the majority of the scenes on the ledge were set to be shot on the real ledge of the Roosevelt Hotel, over 200 feet above 45th Street in midtown Manhattan.
At around the 80 minute mark, one of the bystanders among the crowd starts chanting "Attica, Attica!", echoing the character "Sonny" played
by Al Pacino in 'Dog Day Afternoon' (1975). Attica references a prison revolt that ended tragically, where law enforcement was blamed for excessive force and the death of both prisoners and prison guards alike.
The architectural building model used in the scenes with Ed Harris (beginning around 47:34), in which Harris' character, David Englander, shares his real estate development plans of the "Monarch Spire" to a group of investors, also appears in Brass Tacks (2013). In that episode, Matt Bomer's character, Neal Caffrey pitches a slightly modified version of this same skyscraper model as "The Edwards City Tower" to real estate tycoon, Cole Edwards. (scenes starting around 18:54)