Clinging to a 6-3 lead with 14:21 left, linebacker Gerald Hodges sacked quarterback James Vandenberg and forced a fumble recovered by Nate Stupar at the Iowa 49.
The Nittany Lions (5-1, 2-0) pounded away at the tired Hawkeyes with 10 straight runs to the 2 before McGloin rolled right to find wide-open tight end Kevin Haplea a 13-3 lead with 8:08 to go.
It was more than enough cushion for Linebacker U's tough defense. Vandenberg threw two interceptions over the last seven minutes and Iowa (3-2, 0-1) stumbled in its conference opener after a bye last week.
As was the case the previous two weeks, Joe Paterno coached the first half from the sideline before retreating to the press box after halftime. The 84-year-old Hall of Famer is getting over a sore right shoulder and pelvis suffered when receiver Devon Smith accidentally ran into him at practice Aug. 7.
It was the Hawkeyes absorbing the big blows on Saturday.
Iowa seemingly regained momentum in the tense affair after Micah Hyde intercepted a poor throw by McGloin in the end zone on third-and-5 from the 6, thwarting what had been a nice drive that started the Nittany Lions 4.
But as it has all season, Penn State's defense came through again.
Hodges got to Vandenberg on the blitz on third-and-7 from the Penn State 45, forcing a fumble that had the 105,00-plus fans rocking creaky Beaver Stadium.
Vandenberg finished 17 of 34 for 169 yards, while tailback Marcus Coker had 74 yards on 18 carries.
Coach Joe Paterno opted to go with the ground game after the fumble recovery, rotating carries for Redd, bruising backup tailback Curtis Dukes (60 yards on nine carries) and fullback Joe Suhey before McGloin found Haplea for a TD.
The sophomore tight end exchanged leaping high fives with teammates as blue-and-white fans frolicked in the stands. Not only did the score give Penn State a 10-point lead, but Haplea also scored his first career touchdown.
It only got worse from there for Iowa.
Safeties Malcolm Willis and Nick Sukay each picked off Vandenberg down the stretch. Then Penn State's defense sacked the quarterback on three straight plays with less than three minutes left to push Iowa to a 4th-and-39 from their 1.
Iowa had come into the game averaging nearly 38 points and 281 passing yards a game.
Anthony Fera's two first-half field goals made up for more early red zone hiccups for Penn State, which again rotated McGloin and Rob Bolden at quarterback with middling results.
McGloin again looked a little better and finished 12 of 19 for 133 yards, while Bolden was 3 of 7 for 31 yards.