Hill rushed for a touchdown from the 4 to cap a 10-play, 75-yard game-opening drive, and with 10 minutes to go in the second quarter the BearKats led 17-0.
De'Andre Brown ran in 5 yards for a touchdown, and Parker McKenzie completed a 64-yard pass to Noah Cheshier on Abilene Christian's next possession to cut the difference to 17-14, with 4:08 left in the first half.
The BearKats scored the next three touchdowns to pull away once more.
Johnson threw for 277 yards and Sam Houston (3-4, 2-1 Southland) finished with no turnovers.
McKenzie accounted for 385 of 445 total yards for Abilene Christian (4-4, 2-2). He threw for one final touchdown pass with 2:08 to go, cutting the Wildcats' deficit to 17.