Likewise, Andy Griffith (though a real Southerner) may have played a hick in his early comedy, but also did some good acting in non-Southern roles. Minnie Pearl was actually a dignified and intelligent lady who taught Methodist Sunday School. Gordie Tapp and Don Harron -- second-banana stars on Hee-Haw -- were Canadians, for heaven's sake.
My take is, a persona is just that, a role, a stage identity. Some personae are closer to the actual people who portray them than others, but ALL of them that are any good come from somewhere deep inside the actor, and NONE of the actors who portray them are the same as their stage personae on the street.