The previous record of 21 points was set just last season by guard Lou Williams, who is now coming off the bench for the Los Angeles Lakers.
Previously having an unspectacular night, Lowry found his team trailing 66-57 at the beginning of the fourth quarter with just nine points to his name.
He had 16 of his team's 18 points during one stretch in the middle of the quarter, even picking up an assist on the lone basket he didn't score.
Lowry did get some help to set the record, as he was fouled by Hawks guard/forward Kent Bazemore with just 11 seconds remaining, even though Atlanta had no chance to come back from a 94-86 deficit.
Lowry promptly hit both of his free throws, first tying and then passing Williams' single-quarter franchise record of 21 points. Toronto ended up outscoring Atlanta 39-20 in the final period, making up for an otherwise lackluster performance.
Even with the spectacular finish, Lowry had a stat line that wasn't too far ahead of his usual standards, finishing with 31 points, five rebounds, five assists, two steals and two turnovers in 37 minutes.