Tajouri-Shradi scored for the fourth consecutive match as NYCFC (4-3-2, 14 points) earned points for the sixth time in their past eight matches.
Atlanta United (2-2-5, 11 points) had its five-game point streak snapped with the loss and was shut out for the second time this season in MLS play. The first occurred April 17 in a scoreless draw against Orlando City.
It was the first meeting between the teams since Sept. 25, 2019.
Tajouri-Shradi's goal was the reward for New York City's dominance in the midfield and edge in scoring chances throughout the majority of the match to that point.
A giveaway near midfield by Atlanta led to the goal. Midfielder Keaton Parks gained possession and delivered a pinpoint entry pass to forward Valentin Castellanos, who fired the ball to Tajouri-Shradi inside the 18-yard box.
Tajouri-Shradi then angled a ball past Atlanta goalkeeper Brad Guzan, who made six saves as New York City put frequent pressure on goal.
NYCFC outshot Atlanta 18-6 and 7-3 in shots on goal.
One of the best chances that didn't find the mark was created by NYCFC midfielder Maximiliano Moralez when he nearly scored off a cross from Parks in the 61st minute.
Atlanta coach Gabriel Heinze was absent while serving a one-game suspension due to yellow-card accumulation. Assistant coach Mariano Toedtli took charge in his place.