Hill took over and offered Paddy Chayefsky as Lehman's replacement. Mackendrick suggested Clifford Odets, the playwright whose reputation as a left-wing hero had been tarnished after he named names before the House Un-American Activities Committee. Mackendrick assumed that Odets would need only two or three weeks to polish the script, but he took four months. The director recalled, "We started shooting with no final script at all, while Clifford reconstructed the thing from stem to stern". The plot was largely intact, but in Mackendrick's biography he is quoted from Notes on Sweet Smell of Success: "What Clifford did, in effect, was dismantle the structure of every single sequence in order to rebuild situations and relationships that were much more complex, had much greater tension and more dramatic energy". This process took time, and the start date for the production could not be delayed. Odets had to accompany the production to Manhattan and continued rewriting while they shot there. Returning to the city that had shunned him for going to Hollywood made Odets very neurotic and obsessed with all kinds of rituals as he worked at a furious pace, with pages often going straight from his typewriter to being shot the same day. Mackendrick said, "So we cut the script there on the floor, with the actors, just cutting down lines, making them more spare – what Clifford would have done himself, really, had there been time". Tony Curtis had to fight for the role of Sidney Falco because Universal, the studio to which he was contracted, was worried that it would ruin his career. Tired of doing pretty-boy roles and wanting to prove that he could act, Curtis got his way. Orson Welles was originally considered for the role of J. J. Hunsecker. Mackendrick wanted to cast Hume Cronyn because he felt that Cronyn closely resembled Walter Winchell, the basis for the Hunsecker character in the novelette. Lehman makes the distinction in an interview that Winchell was the inspiration for the version of the character in the novelette, and that this differs from the character in the film version. United Artists wanted Burt Lancaster in the role because of his box office appeal and his successful pairing with Curtis on Trapeze. Robert Vaughn was signed to a contract with Lancaster's film company and was to have played the Steve Dallas role but was drafted into the Army before he could