The midfielder was a substitute in the 1-0 defeat in South Yorkshire, a goal from Liam Palmer just before half-time settling it.
On Friday night Johnson signed a new two-and-a-half year contract, completing the formalities at the team hotel.
It keeps him contracted to North End until the summer of 2023.
Johnson said: “It has been hanging over my head for quite a while now so I’m delighted it is done and I can focus on football.
“There were loads of different things which got me to the point where I signed, I’m not going to go into too much detail about it.
“But I’m happy it is done and I can look forward now.”
Speculation over whether Johnson would sign has added to a busy January at Deepdale.
Alan Browne was in the same boat until a fortnight ago when he agreed a new deal.
Then there has been all the transfer activity, both in and out of North End, with more possibly to come ahead of Monday night’s cut-off.
Johnson said: “Things can hopefully settle down.
“The ins and outs are part and parcel of football – Ben Pearson and Darnell Fisher leaving – people move on and you get on with.
“I’ve really enjoyed my time here and hopefully I can go on to enjoy the next two-and-a-half years.
“This is a really good club for me, I’ve been here six years so I’m really settled.”
North End’s defeat to the Owls was a disappointing spectacle.
The visitors had the better of the game but offered little threat going forward.
Johnson replaced Ryan Ledson in the 67th minute to try and give PNE more attacking impetus.
Said Johnson: “We were on top for long spells of the first half and that is when we needed to score.
“That would have opened Wednesday up because they are stubborn in their shape.
“Their goal made it easier for them to put everyone behind the ball. The first goal is often key and unfortunately we didn’t get it.”
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