Jeff Foxworthy was born in Atlanta, Georgia, and was raised in the nearby suburb of Hapeville, seven miles south of downtown Atlanta. His father was an executive at IBM, and Jeff attended Hapeville High School, and later Georgia Tech, before also working at IBM as a repair person on large mainframes. He left his computer career to begin working in stand-up comedy in 1984, and gained fame in the early 1990s.
Jeff Foxworthy has acknowledged in interviews that working at IBM is not stereotypically a "redneck" occupation, but that what makes him a "redneck" is a "glorious lack of sophistication". I don't think we need to make a purity test for who is a redneck, but I do feel there is a gap between the actual lives of self-proclaimed rednecks, and the lives they celebrate. Hapeville, Georgia includes part of Atlanta Hartsfield-Jackson International Airport, which was (up until a few weeks ago) the world's busiest airport. The entire history of Hartsfield-Jackson is a long one, and while it was not the world's busiest airport until 1998, it was already the biggest in the 1970s, before Foxworthy launched his comedy career. His high school was located less than a mile from a runway of that airport.
Again, I am not saying this to paint Foxworthy as somehow dishonest, but it shows how preconceptions and implications can sneak into a culture. Foxworthy was raised in an upper middle-class, suburban setting, very close to one of the world's largest transportation portals. While he has never denied this, his personality or persona does imply otherwise. The reality of what life is like for the rural or working class, both traditional parts of what it means to be "redneck", have been somewhat occluded by the media image put forward by figures like Foxworthy.
Jeff's official brief autobiography on his origin: http://www.jefffoxworthy.com/timeline/jeff-wins-great-southeastern-laugh-off
An interview where Jeff talks about what it means to be a redneck: http://content.time.com/time/arts/article/0,8599,1924965,00.html
The history of Atlanta International: http://www.atl.com/about-atl/history-of-atl