Heinen started the day tied for third, three shots behind Weatherford's Quade Cummins. After carding birdies on holes 11-13, he was 6 under par.
He finished with a 3-under 69 for a 141 total to defeat Cummins by three strokes. Edmond North's Tyson Reeder, Oklahoma Christian's Zac Schaefer and Laverne's Mason Overstreet tied for third at 147.
ALL-CITY BASKETBALL GAMES THIS WEEK
Now that most schools have wrapped up the year, it's time for all-star games in a variety of sports to start taking place.
It begins this week with the Little and Big All-City basketball games.
The Little All-City basketball games will tip off with the girls at 6:30 p.m. Tuesday night at Redlands Community College in El Reno.
The Big All-City boys and girls games will be Thursday at Del City. The girls game will tip off at 6:30 p.m. and the boys will follow at 8.