In 2255, in the Kelvin timeline, Christopher Pike found a young James T. Kirk brawling in an Iowa bar and challenged him to join Starfleet.
Kirk had grown up without his father, who died aboard the USS Kelvin on the day he was born, and he drifted toward trouble. After a fight with a group of cadets in a bar near the Riverside shipyard, Pike approached him and told him how George Kirk had saved hundreds of lives.
Pike dared him to enlist, and the next morning Kirk joined the recruits leaving for Starfleet Academy, meeting Leonard McCoy aboard the shuttle. Three years later he would take the Kobayashi Maru test and then serve aboard the Enterprise.