This was the first film that showed zombies close to how we know them today, followed four years later by George Romero and John Russo’s classic Night of the Living Dead, which is the true playbook for all modern zombie movies.
The Last Man on Earth has some elements that can be seen in Living Dead, though. Probably the most important element is slow-moving zombies. Matheson’s I Am Legend portrays the afflicted (i.e., zombies, but they weren’t called that in the book) as fast moving and quite agile, like in the 2007 movie version of I Am Legend starring Will Smith.
*Fun fact: Matheson helped write The Last Man on Earth, but the final version was different enough that he asked that his name be credited as Logan Swanson.