P.J. Hairston had 15 points and James Michael McAdoo added 14 for the Tar Heels (13-5, 3-2 Atlantic Coast Conference).
With former star Rashad McCants watching from behind their bench in a McAdoo jersey, the Tar Heels never trailed and shot nearly 43 percent (30 of 70) to move above .500 in league play for the first time this season.
Kammeon Holsey had 10 of his 18 points in the first half, but the Yellow Jackets (10-7, 0-5) had 19 turnovers and lost their fifth straight to remain the only team winless in ACC play.
Still, they trimmed a 13-point deficit to 36-32 on Solomon Poole's 3-pointer with 2 minutes left in the half.
Bullock - who had a career-high 24 points last time out against Maryland - started and finished the ensuing 15-2 run with buckets from close range. His no-you-take-it layup from Marcus Paige gave the Tar Heels their largest lead to that point, 49-34, with 17½ minutes to go.
Georgia Tech never got closer than 11 the rest of the way, and Hairston punctuated this one with a thunderous dunk over Daniel Miller with about 6 minutes left that made it 70-53.
Chris Bolden finished with 10 points while Robert Carter had 12 rebounds and Marcus Georges-Hunt added 10 boards for Georgia Tech, which lost at each of the points in the North Carolina Triangle - N.C. State, Duke and now UNC - in a stretch of 15 nights.
Dexter Strickland and Paige each finished with six assists for North Carolina, and the only thing its students love as much a Tar Heel victory is a Duke loss. One held a handwritten sign saying only "didDukewin.com" while another one nearby held a sign that said simply "No" because a few minutes before this one tipped off, No. 25 Miami polished off a 90-63 rout of the top-ranked Blue Devils.
When that score went up on the video board during a timeout, the crowd followed with a loud, sustained ovation and the students chanted "Go to hell, Duke!"
Then the Tar Heels themselves got clicking, building their first double-figure lead while holding Georgia Tech without a field goal for 4½ minutes. McAdoo's dunk from the baseline with 9½ minutes left put them up 25-15 and brought McCants - who starred on the 2005 national championship team - to his feet.
The lead grew to 13 on Bullock's 3-pointer with 8 minutes left before the Yellow Jackets rallied.
Earlier in the day, the Tar Heels found out they'll be without junior guard Leslie McDonald for three more games. He missed the previous three games with a knee injury, but was suspended for three more after coach Roy Williams said he "did not do what we expect of our student-athletes."