Over the decades, Richard Matheson’s 1954 novel I Am Legend has spawned a series of iconic horror and science-fiction films, including The Last Man on Earth (1964) starring Vincent Price, The Omega Man (1971) featuring Charlton Heston, and I Am Legend (2007) with Will Smith. Its compelling narrative about the last man on earth struggling to survive a pandemic that has transformed the rest of humanity into monsters has arguably become an American myth. While its core story remains intact, filmmakers have transformed its details over time, their often mixed messages reflecting changing attitudes about race and masculinity in the United States. This reexamination of Matheson’s original novel situates its tale of a man’s conflicted attitude about killing racialized others within its post-World War II context, engaging the question of post-traumatic stress disorder. It then analyzes in turn the novel’s several film adaptations, focusing in particular on producers’ choice of actor to bring to life Robert Neville, the last man on earth. Released respectively during the Cold War and the Civil Rights Movement, the Vietnam War, and then much later in the post-9/11 era, these films reveal America’s ongoing struggle with racial conflict and the construction of masculinity.