Emraan plays a rising don in the film and sports flared bell bottoms, long hair and huge sunglasses as part of his character. He even sports a luxurious moustache, as director Milan Luthria felt it would make Emraan look more mature.
Once Upon A Time In Mumbaai is set in the 1970s. Emraan plays Shoaib, who has marked similarities to Dawood. Ajay Devgn plays Sultan Mirza, said to be based on Haji Mastan. The two female leads are played by Kangna Ranaut and Prachi Desai.