Campbell made the announcement Thursday on Twitter, posting a video of himself with one finger raised and the caption: "One more."
ESPN's Mel Kiper rated Campbell, a redshirt sophomore, as the No. 9 draft-eligible wide receiver for 2018.
Campbell had 40 receptions for 583 yards and three touchdowns this past season, his second as a starter. He eclipsed 100 receiving yards twice in the first four games but had only two receptions in Ohio State's final two contests.
Also on Thursday, Buckeyes wide receiver Johnnie Dixon announced on Twitter that he'll return as well.