Marshall coach Doc Holliday announced Smith's transfer Thursday.
Smith, a senior, will be eligible to play this season because of the NCAA's penalties against Penn State following the Jerry Sandusky child sex abuse case.
The 5-foot-7, 147-pound Smith caught 25 passes for 402 yards and two touchdowns at Penn State last season. He also returned kicks.
Smith is the second former Nittany Lions player to transfer to Marshall, joining junior cornerback Derrick Thomas.