This is the film that made Amitabh Bachchan a superstar and started the series of "angry-young-man-films".
The making of the film "Zanjeer" was beset with problems. Pran who played the Pathan was reluctant to sing or dance . On the very first day he threatened to walk out of the floor. Mehhra had to rush to pran's house to plead with him, saying without him the film would not work as Amitabh as a hero was not a bankable box office proposition. Finally song was shot and Pran gave one one of the best performances of his career. "Yari Hai Iman Mera Yaar meri Zindagi" lipped by Pran made a history.
The lead role had been initially offered to Raaj Kumar, who refused to work with Prakash Mehra on the grounds that he could not stand the smell of the latter's hair oil!
Amitabh Bachchan got the film after writers Salim Javed spotted is talent in Bombay To Goa 1972.
During the making of Zanjeer, Ajit asked the director if he had met Haji Mastan and others. He had observed that when they spoke, they didn't speak loudly. Instead, they spoke in a very sophisticated manner and were always smiling. So he changed the way a villain speaks with this movie. The truth is that Salim Khan knew a don in Bhopal or Indore and wrote the character based on that guy. He took Ajit to meet that person and dad stayed with that gentleman for a week, studied him and then portrayed him on screen.