Smith's field goal, his third of the game in three attempts in swirling winds, came after the Lions' Sam Ficken, who had missed an extra point after his team's first touchdown, sliced a 37-yard field goal wide right on the initial possession of overtime.
This wasn't the way the Lions (6-5, 3-4 Big Ten) wanted to send off their seniors, even though they'll have one more chance next Saturday at Wisconsin.
The defense held up its end with two goal-line stands - the first resulting in a lost fumble by Nebraska running back Ameer Abdullah, the second forcing Smith's tying 19-yard field goal with 4 minutes, 29 seconds left in regulation instead of a go-ahead touchdown.
"We fought the entire game," senior middle linebacker Glenn Carson said. "Especially on the goal line, we had that bend-but-don't-break mentality we've been kind of talking about all year, and that's what we did."
But the offense and special teams were lacking against the Cornhuskers (8-3, 5-2). Christian Hackenberg threw for two touchdowns and ran for one. His second TD throw - a 36-yarder to tight end Jesse James on the first snap of the fourth quarter - gave the Lions their third lead of the game at 20-17.
However, not counting their TD drives and overtime, the Lions got inside the Nebraska 40 only one other time - on their last drive of regulation. They stalled at the Huskers 38 with less than two minutes to play.
"Every time we get a couple of big plays and we start stringing them together, we usually move the ball well and we get some points," said Hackenberg, who finished 16 of 33 for 217 yards and one interception. "But it didn't happen. It's a little frustrating, but we regrouped and got it into overtime. But things just didn't go our way today."
On special teams, the Nittany Lions allowed a kickoff return for a touchdown - a 99-yard dash by Cornhuskers wide receiver Kenny Bell - for the second consecutive week.
"That's not good," coach Bill O'Brien said. "The kids are trying hard, though. They're good kids. We've just got to continue to try to work on it and fix it. We work hard on special teams and we'll continue to work hard on special teams this coming week."
In addition to Ficken's missed extra point and field goal, the Lions' special teams were guilty of allowing a blocked punt after Alex Butterworth fumbled the snap.
Bell's kickoff return and Smith's second field goal, a 39-yarder, gave Nebraska a 17-13 lead. But the Hackenberg-to-James TD connection, on which James did an excellent job of staying in bounds along the left sideline, put the Lions up one more time.
Abdullah, who rushed for 147 yards in 25 carries, later had a 62-yard touchdown run nullified on a personal-foul penalty. The Cornhuskers regrouped and looked as if they were going in on a scramble by quarterback Ron Kellogg III, but linebacker Mike Hull met him head-on at the 1 to force the field goal.
But unlike the other two overtime Big Ten games that they pulled out, the Nittany Lions couldn't get this one.
"We felt really comfortable in overtime," Carson said. "I think everybody on our team felt we were going to get it done, but it just didn't go our way this time."