Denison got the ball first in overtime and kicked a field goal to take a 24-21 lead. Wittenberg answered with a quick strike on its second play in overtime to end a three-game losing streak in the series. May caught the ball in the back of the end zone as he and a defender jumped at the same time.
Wittenberg beat Denison for the first time since a 68-66 four-overtime victory in Granville in 2018.
Wittenberg (3-1, 2-0) stayed unbeaten in the North Coast Athletic Conference and bounced back from a 48-28 loss to No. 19 Alma a week earlier in Springfield.
Denison (3-2, 2-1) fell out of a first-place tie with DePauw (5-0, 3-0), which beat Oberlin 66-7 on Saturday. Wittenberg is tied for second place with Wabash (3-1, 2-0), which won 31-13 at Ohio Wesleyan.
Against Denison, Wittenberg overcame an early 7-0 deficit with 21 straight points.
Milton threw a 74-yard touchdown pass to Dean Tate to tie the game early in the third quarter. Milton then connected with Troy Teepe for a 10-yard touchdown with 6:05 left in the third as the Tigers took a 14-7 lead. A one-yard run by Bryce Anderson early in the third quarter extended the lead to 21-7.
Denison tied the game with two late touchdowns. Trey Fabrocini scored on an 8-yard run with 7:28 to play. Jimmy Stines threw a 20-yard touchdown pass to Josh Aiello with 1:09 remaining.
Milton completed 22 of 37 passes for 294 yards with three touchdowns and an interception. Tate caught nine passes for 193 yards.
Wittenberg returns to action against Hiram (0-5, 0-3) on homecoming at Edwards-Maurer Field at 1 p.m. next Saturday.