Larlham shared offensive player of the year honors with Beloit West Branch quarterback Ben Swallow, while O'Neill and Rardin were the defensive player and coach of the year, respectively.
The selections were based on recommendations of a state media panel.
Larlham is a 6-foot, 210-pound senior who completed 90-of-150 passes for 1,400 yards and 8 touchdowns with 4 interceptions. The Michigan State signee also ran 94 times for 770 yards and 14 touchdowns.
Swallow, a 6-2, 185-pound senior who was a first-team All-Ohioan last year, passed for 1,609 yards and 13 scores and ran for 1,106 yards and another 12 touchdowns.
O'Neill, who has committed to Ohio State, was credited with 130 tackles, including 12 for negative yardage, and four sacks. The 6-4, 220-pound senior was a force all season for Walsh, which plays Columbus DeSales Saturday afternoon in Canton for the state championship.
Rardin was at the controls as Walsh rolled over 10 straight opponents, mostly by lopsided scores.