* CareerResurrection: Robert Blake had been a popular child actor, most notably as a member of the famous Little Rascals, but his adult career had mostly been small parts and supporting roles. His performance as Perry Smith gave him a second wind and launched a successful adult career for the next thirty years.
* DarkhorseCasting: Aspiring to recreate a documentary aesthetic for the film, Richard Brooks deliberately cast actors who were relative unknowns.
* PlayingAgainstType: Creator/AnthonyEdwards, at the time known for his role as ''Series/{{ER}}'' nerdy NiceGuy Mark Greene, played Dick Hickock in the 1996 MiniSeries.
* StarMakingRole: Scott Wilson had only appeared in one film prior to this and his performance as Dick Hickok made him a popular character actor virtually overnight.
* ThrowItIn: The famous shot where the reflection of the rain on the window looks like tears running down Perry's face wasn't originally planned. The wind machine misted up the window while cinematographer Conrad Hall was lighting the scene and caused the effect on Creator/RobertBlake's stand-in, which he pointed out to director Richard Brooks.
* WhatCouldHaveBeen:
** Creator/ColumbiaPictures originally wanted Creator/PaulNewman and [[Creator/SteveMcQueenActor Steve McQueen]] as Richard Hickock and Perry Smith, respectively, but Richard Brooks refused as he felt their star statuses would render their performances less believable to audiences. Furthermore, Newman was busy with ''Film/CoolHandLuke'' and ''Film/{{Hombre}}'', while [=McQueen=] was busy with ''Film/{{Bullitt}}'' and ''Film/{{The Thomas Crown Affair|1968}}''.
** Creator/LeeMarvin wanted the role of Alvin Dewey, but Brooks gave it to John Forsythe instead. Brooks had worked with Marvin on ''Film/TheProfessionals'', but Marvin had proved to be a handful on the set.
** Creator/DannyDeVito sought out the role of Perry Smith at the start of his acting career. He would not make his film debut until 1970.
** Creator/OttoPreminger had tried to buy the rights to the novel in 1965, and planned for Creator/FrankSinatra to star.
** Columbia wanted Music/ElmerBernstein to compose the score but Brooks insisted on hiring Music/QuincyJones instead. Jones composed his score alongside the filming.
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