Substitute Alex Jones, who played the first half of the season on loan at Port Vale, scored his first goal for the Bantams just two minutes after coming on to help claim a morale-boosting success for McCall's men at Vale Park.
Skipper Romain Vincelot had given City the lead shortly before the break but Vale striker JJ Hooper drew the hosts level in the second period.
Jones had the final say, however, netting the match-winner. in front of a delighted away end shortly after his arrival on the pitch.
The win moves the Bantams back up into fifth in the Sky Bet League One, and it comes after a recent run of frustrating results for City where they perhaps didn't get the points their performances merited.
McCall: "We knew today (Saturday) was all about the result.
"We have probably played better this season and not won, but we know the result is the main thing at this stage of the season.
"After twenty minutes or so, we thought it might be the same old story for us.
"We've created a number of good chances and we just hoped they wouldn't come back to haunt us.
"We felt set-pieces could be key for us because, for once, we actually had a height advantage.
"We'd been working on them in the last couple of days, and we get a goal from one to see us deservedly in the lead at the break.
"Vale are fighting for their lives at the bottom, so we knew they would come back at us.
"They get a goal out of nothing really and it became a mental test for the lads, especially after being ahead against Fleetwood and Bolton recently and not going on to win.
"The crowd were up in their favour at that stage but it was good to see the lads come back and show some mental strength.
"You always want substitutes to make an impact, and two of them have today with Alex Gilliead and Alex Jones combining for our winning goal.
"Charlie Wyke had been suffering with a bit of flu during the week and Nicky Law got a knock earlier in the game, so we will have to check them ahead of Tuesday (vs MK Dons).
"The main thing at the moment, however, is the three points. I am pleased for the fans, the players and the staff that we've managed to get this result.
"It has been a tough few weeks after not getting what we've deserved from recent games, so this is a welcome win.
"We won't rest on our laurels - we know we can do some things better - but we'll go into Tuesday's match with renewed confidence."
Match-winner Jones wasn't originally due to play against his former club after only recently returning to training following a hip problem.
The January recruit was given the green light to make the trip to Vale Park, however, after impressing on the training ground, and he repaid the faith shown in him by picking up his maiden City goal.
McCall said: "We've been really happy with Alex, he just hasn't really had any chances in any of the games he had played previously.
"We've seen in training what a good finisher he is and he's shown that this afternoon as well.
"When I spoke to the press on Thursday about Alex I wasn't lying when I said he wasn't going to be involved in this game.
"He came in on Friday, however, and he said he felt great. We let him train and he looked very sharp.
"I spoke to him and the physios afterwards and they said there had been no reaction.
"With Charlie (Wyke) struggling with illness and Marshy (Mark Marshall) out injured, we thought he could go on the bench with the idea of maybe giving him the last twenty minutes or so if needed.
"I'm naturally delighted for him to get the winner, he'll certainly be on a high.
"There is definitely something about players going back to their old clubs."