Sampson, who entered the game averaging 6.7 points and seven rebounds, also added 17 points. Kemp, who scored nine of his points from the free-throw line, grabbed 11 rebounds for the Pirates (4-0).
Appalachian State (1-3) scored the game's first four points and led 6-2 after Nathan Healy hit a jumper. But East Carolina used a 14-4 run to go ahead 16-10 with 14:29 left in the first half.
Appalachian State cut the deficit to 23-22 later in the half but would not get any closer as East Carolina took a 38-33 advantage into halftime and never led by less than four in the second half.
Jay Canty had 25 points and Healy added 24 points and 10 rebounds for Appalachian State.