Illinois (6-3, 2-3) drove from its 17 to the Penn State 25, but Derek Dimke's 42-yard field-goal attempt bounced off the right upright as time expired.
Redd had a career-high 30 carries for 137 yards for Penn State, none bigger than his late run set up after Illinois corner Justin Green was whistled for pass interference after breaking up a fourth-down pass for Derek Moye in the end zone.
Among all coaches, Paterno trails only John Gagliardi, still active at Division III St. John's, Minn., with 481 victories.
"It really is something I've very proud of, to be associated with Eddie Robinson," Paterno said in a brief postgame ceremony in the media room broadcast to fans still waiting in the stands 10 minutes later. "Something like this means a lot to me, an awful lot. But there's a lot of other people I've got to thank."
The Nittany Lions' 84-year-old leader watched from the press box on a snowy day in Happy Valley that had fans bundled up in winter parkas and hoodies. Paterno's right leg and shoulder are still sore after an accidental hit in practice in the preseason.
After struggling most of the afternoon, quarterback Matt McGloin drove Penn State from its own 20 to the Illini 32 on three long completions before the pass interference call gave the Nittany Lions a second chance. Redd capitalized four plays later by barreling into the end zone.
Jason Ford rushed for 100 yards on 24 carries but Illinois couldn't capitalize on a slew of Penn State mistakes in a defensive slugfest.