Campbell is only second behind club legend Jimmy Mullen, as being the youngest to ever wear a Wolves senior jersey.
He made his debut at Aston Villa in October 2019, but has since been on loan four times.
On Campbell, who is at Reading this term, Jackson stated: “It’s just a maturity thing. He’s such a lovely young man, well brought up, you just want him to unleash himself.
“You see him do things in training where he's got an ability level that's fantastic, but you just feel like you're wanting him to go and really grab one of these loans and be the main part of one of these teams. He's had that impact again at Reading.
“He's been a victim of circumstance in some ways. Some of the clubs have had a quick turnover of coach when he's gone in, things that are out of his control, but the one thing he can control are his performance and output on the pitch, that's the thing we've really challenged him with.”