The Irishman's 19 top-flight home games during his spell in charge on Wearside failed to yield a single win as his shoestring budget proved woefully inadequate on Saturday.
However, his current employers took a huge stride towards booking their place in next season's Premier League with a 3-1 victory on top of their derby success against West Brom last weekend.
Second-half goals from Steven Fletcher - his sixth in eight games - and George Elokobi in front of delighted vice-president and Led Zeppelin star Robert Plant eased the visitors over the line after Stephane Sessegnon had cancelled out Black Cats old boy Jody Craddock's 23rd-minute opener.
The defeat was injury-plagued Sunderland's seventh of the season in the league on their own park in front of a largely disappointed crowd of 41,273.
Steve Bruce's men, who secured their own status with victory at Bolton last Saturday, were furious not to be awarded a 62nd-minute penalty for Stephen Hunt's challenge on Sessegnon with the score at 2-1, but they defended so poorly that even that might not have brought any reward.
McCarthy returned to Wearside knowing three points to go with the ones they collected last weekend would go a long way towards guaranteeing their top-flight status.
But it was another ex-Black Cat who made the breakthrough when Craddock, who scored just twice in 171 appearances for the Wearsiders, thumped home a 23rd-minute volley from Hunt's cross to give the visitors a dream start.
The goal came distinctly against the run of play with Bolo Zenden having earlier rattled the angle of bar and post with a powerfully-struck left-foot effort which left keeper Wayne Hennessey rooted to the spot.
Hennessey, however, was far more pro-active with 18 minutes gone when he dived to his right to palm away Sessegnon's drive.
The woodwork came to Sunderland's rescue 14 minutes later when Jamie O'Hara's dipping shot eluded keeper Simon Mignolet but not the crossbar, and Wolves' despair was to increase within two minutes.
Zenden's right-wing corner was allowed to bounce inside the six-yard box and the unmarked Sessegnon acrobatically volleyed home from five yards to level.
The half ended with Sunderland firmly in the ascendancy despite the selection problems which had robbed Bruce of an entire starting XI, but with the visitors still firmly in the hunt and believing they might have had a penalty for handball against John Mensah as he blocked Stephen Ward's cross.
McCarthy made a change at the break when he replaced midfielder Adlene Guedioura with Matt Jarvis, and the England international won an early corner which the home defence dealt with less than convincingly.
Fletcher passed up a glorious 49th-minute opportunity to restore his side's lead when he beat the offside trap to home in on Mignolet, but full-back Ahmed Elmohamady covered across well as he and Mignolet squeezed him out.
Hennessey had to be at his best to tip Steed Malbranque's deflected shot over the bar two minutes later, but the momentum was shifting and it did so dramatically with 54 minutes gone.
Jarvis skipped past full-back Bardsley on the right and dinked the ball to the far post, were Fletcher climbed high above Mensah to head home with Mignolet having horribly misjudged the flight.
The home side survived a dreadful misunderstanding between Mignolet and Mensah five minutes later, but they were convinced they should have been awarded a 62nd-minute penalty for Hunt's challenge on Sessegnon, although replays suggested referee Mike Jones had made the right decision.
Bruce introduced Ryan Noble in place of Malbranque with 20 minutes remaining, and he was soon followed by Republic of Ireland international Kevin Doyle, who replaced Fletcher on his return from a lay-off of almost two months with knee ligament damage.
The striker won a corner within two minutes of his arrival from which Elokobi headed just over with the home side once again less than effective in defence.
But the defender was more accurate 12 minutes from time when he met O'Hara's free-kick with a diving header to seal the win.