Idalou (12-3) won its first state championship in its first title-game appearance.
Lexington (14-1), in its first championship game since 1978, was also bidding for its first state title.
Idalou was 1-3 after its first four games but rode a stingy defense to the title. Idalou allowed just 27 points during its 11-game winning streak, including just 15 points in five playoff games.
Idalou held Lexington to 186 yards, including just 5 yards on the ground.
Idalou, led by defensive MVP Matthew Sales, recorded seven sacks. Estes was named offensive MVP.
Idalou ran just 14 offensive plays in the first half yet held a 6-3 lead at the break.
Lexington's only points came on a 37-yard field goal by Antonio Martinez on its first drive of the game.
Schilling recovered a fumble in the end zone for Idalou's second touchdown, and Idalou scored again seven plays later.
Estes found tight end Brent Turner wide open for a 74-yard touchdown, and the two connected again on the two-point conversion for a 20-3 lead with 1:41 left in third quarter.