Very little is known about Jackson, except that he's been working in the San Andreas Flight School as an instructor at some point in GTA V. He is not seen in person; his voice is heard only during the various lessons of Flight School.
Jackson is considerably calm, nicer and more encouraging than his Onlinecounterpart. Every time, Jackson is telling the player what he/she has to do during the course of the lesson, and he has a bit of a sense of humor, as seen during the same.
If the player gets a gold medal, he always congratulates him/her for the success in the lesson. If the same gets silver or bronze, then he tells the player that the lesson was fine, but it could be better.