Timberwilde Elementary was put on lockdown on Monday morning as police searched the campus for the suspect in a nearby burglary.
San Antonio police officials said said they were first called out to Gene Brown Transmission at 2045 Grissom Road for a report of a car burglary at around 8:30 a.m.
The suspect was tracked down to the elementary school, which is about a block away from the shop.
The San Antonio Police Department's Blue Eagle helicopter scanned the area from above as dozens of police officers and a K-9 unit checked the school grounds.
After about 30 minutes, the suspect was found just outside of the school building.
Police said he was unarmed and was arrested without incident on the playground.
According to Northside ISD spokesman Pascual Gonzalez, the lockdown probably prevent the suspect from entering the school.
Gonzalez said about 70 children were inside at the time of the lockdown.
It was the first day of a Parks and Recreation Department summer program being held at the school.
After the incident, school resumed as usual.
Gonzalez said students will be sent home with letters to alert their parents of the situation.