Here is who John Connor's father is in the original Terminator timeline. Best known as the future leader of the Resistance in the War against Skynet, John Connor is one of the core heroes of the Terminator saga created by James Cameron. But perhaps the defining trait of John Connor is that he deliberately sends his own father, Kyle Reese, back in time to meet his mother, Sarah Connor, so that they can fall in love and give birth to him.
At the end of 1984's The Terminator, Sarah is shown pregnant with John, who then appears as a 12-year-old (played by Edward Furlong) in Terminator 2: Judgment Day. The adult John, now played by Nick Stahl, fails to prevent Judgment Day in Terminator 3: Rise of the Machines and, in Terminator Salvation, John was played in the future by Christian Bale. Terminator Genisys turned John, now with the face of Jason Clarke into an evil Terminator, but the critical and box office failure of Genisys made that story apocryphal. The upcoming James Cameron-produced Terminator: Dark Fate, directed by Tim Miller, is a continuation of the events of The Terminator and Terminator 2. And yet, despite the various timelines and incarnations of the leader, Kyle Reese remains John Connor's father.
In a classic case of a grandfather paradox, John had to send Kyle back through time to father him (and then die) so that John could exist. In The Terminator, Kyle Reese (Michael Biehn) arrives in 1984 to protect 19-year-old Sarah Connor (Linda Hamilton) from a Terminator out to kill her. Skynet sent back the Terminator to eliminate Sarah in order to specifically prevent John's birth, which would - in theory - change the future since John would not exist to lead the humans to victory over Skynet in 2029. Reese had already fallen in love with a photo of Sarah that John kept with him and, from the stories his mother told him, John knew Kyle was destined to be his father. Terminator Salvation depicts more of the relationship between John and Kyle in 2018, though Connor was much older than Reese, who was played by the late Anton Yelchin.
Terminator Genisys is perhaps the biggest recent factor making fans question who John's father is. In Genisys, Reese (played by Jai Courtney) meets Sarah (Emilia Clarke) in 1984 and together, they time travel to 2017 to prevent the dissemination of the Genisys operating system, which would evolve to become Skynet. But surprisingly, Kyle and Sarah don't fall in love and have sex in Genisys. This deviation from the instantly doomed romance between Sarah and Kyle threw a wrench into Terminator continuity. However, Terminator: Dark Fate is ignoring Genisys entirely so the canonical saga is resetting back to the original timeline established by James Cameron's first two films.
The Terminator timeline has become so convoluted that it's easy for fans to be confused about John Connor's parentage. With so many contradicting timelines and the date of Judgment Day continually getting pushed back, which then changes the timeline and future events, the point of the original John-Kyle-Sarah time loop and paradox that enables the Terminator story to exist in the first place can get lost.
Despite some fans speculating about other possibilities, Kyle Reese being John's father is consistent across the Terminator films and also the TV series Terminator: The Sarah Connor Chronicles, where Thomas Dekker played a teenage John and Jonathan Jackson played Kyle Reese. Even though The Sarah Connor Chronicles exists in a separate timeline unrelated to the movies, it still adheres to the basic history of Cameron's Terminator and T2 that began with a time-traveling Kyle Reese falling in love with Sarah Connor and becoming John Connor's father.
