#21: He Steps Into America’s Biggest Assassination Mystery With JFK in 1991
Also in 1991, he starred in JFK, a sprawling political drama about the unanswered questions and conspiracy theories surrounding President John F. Kennedy’s assassination. The film turned one of America’s most debated historical tragedies into a tense, talk-heavy investigation about power, secrecy, and public doubt.

The role kept Costner tied to serious, high-profile filmmaking at a moment when he could have stayed only in blockbuster territory. Instead, he moved from Westerns and adventure films into one of the most controversial American stories ever put on screen.
