Highland beat Melbourne 54-34 in the first round and Mountain View 50-46 in the second round, while Calico Rock beat Southside 30-23 and Salem 47-14, to set up the championship game.
The junior Rebs, who pressed the junior Pirates nearly the entire game, forced seven turnovers in the opening period to jump out to a 7-4 lead.
Johnson's eight points in the second, including a dunk and 4-of-8 from the line, broke the game open and gave Highland a 21-12 halftime advantage.
Brian Parnell opened the second quarter with a bucket, but Calico didn't score again until two minutes left when Parnell hit two free throws.
Neither team scored until midway through the third. Johnson had six for the Rebels and Corbin Rhodes added two. Austin Pool put in a two and Toby Stone added a trey for the junior Pirates, but Highland extended its lead to 29-17 at the end of three.
Bruce Chandler scored eight and Parnell two for the Pirates in the fourth, but Highland's nine points kept Calico Rock from gaining any ground.
Calico was led by Parnell and Chandler with eight points each and Pool had six. Rhodes and Colby McGuire each had six points for Highland.