The Geordie striker fired home an 82nd-minute equaliser to claim a precious point at the Riverside Stadium after Boro had come from behind to lead.
Scott McDonald's first Middlesbrough goal eight minutes earlier looked to have handed all three points to the Teessiders after Barry Robson had cancelled out Peter Lovenkrands' 16th-minute opener.
But Carroll ensured the derby spoils were shared as the 3,743 travelling supporters among a crowd of 27,347 headed for home with pride and promotion hopes intact.
The home fans were on their feet within two minutes of kick-off when McDonald, back after two games on the sidelines with a groin problem, went down in the box under Fabricio Coloccini's nudge.
However, much to the Australian's disbelief, referee Lee Mason waved play on.
Fitz Hall had to get in an important block to keep out Stephen McManus' sixth-minute shot as the Teessiders started in confident style.
Newcastle were struggling to put together a move of any substance, but they took the lead with 16 minutes gone from their first coherent attack.
Jonas Gutierrez cut in from the left before sliding a perfect reverse pass into the feet of Lovenkrands, who beat keeper Danny Coyne with ease to claim his 13th goal of the season.
It took a fine diving save from Steve Harper, who celebrates his 35th birthday on Sunday, to keep out Robson's 29th-minute free-kick.
But the former Celtic midfielder's persistence paid off nine minutes before the break when he and McDonald combined 25 yards out before curling an unstoppable left-footed shot past the helpless Harper.
Lovenkrands only just failed to find the net after running on to Carroll's injury-time flick-on, but the home side continued to enjoy the better of the game immediately after the break.
Substitute Ryan Taylor, on for the injured Coloccini, turned up in the right place at the right time to take Robson's 52nd-minute cross off Julio Arca's toe at the far post.
Gutierrez floated a 59th-minute cross just over Coyne's bar, but Harper had to make a fine one-one-one save from Arca after O'Neil had pounced on Fabrice Pancrate's poor control two minutes later.
McDonald fired across goal with 25 minutes remaining and Danny Guthrie saw a long-range effort deflected wide at the other end.
But it was the Australian who struck with 16 minutes remaining, turning smartly to steer home from Chris Killen's knock-down.
However, there was a twist in the tail and when Taylor's driven cross fell to Carroll, who was for the first time left free by McManus and David Wheater, he controlled before stabbing home the equaliser.