The name of northern whites who went south to start business or to pursue political careers

The name was "carpetbagger".

A carpetbagger was any individual from the North who went toward the South after the American Civil War and was seen to use the neighborhood people for their own motivations. This extensively included the two people who looked to advance their political agenda and people who saw deceitful business openings due to the disordered condition of the economies following the war.