In 'The Terminator', what is the name of the human resistance leader?

In 'The Terminator', the human resistance leader is John Connor.

John Connor is the future commander of humanity's resistance against Skynet, the artificial intelligence that launches a nuclear war and deploys machines to exterminate survivors. Although he is not yet born during most of the 1984 film's present-day storyline, his future importance drives the plot: Skynet sends a Terminator back in time to kill his mother, Sarah Connor, before John can be born.

Kyle Reese, another resistance fighter, is sent back to protect Sarah. He is therefore closely connected to John Connor's origin, but he is not the resistance leader named in the question. Sarah Connor is John's mother and later becomes a determined fighter herself, while Skynet is the machine intelligence directing the attack.

John's character continues through the franchise, with different actors portraying him at various ages. The first film establishes him primarily as the pivotal figure whose future leadership makes him a target, setting up the time-travel conflict that defines the series.