The teenager, whose identity was withheld due to his age, was detained for questioning shortly after the 10 a.m. shooting Wednesday, culminating in his arrest on suspicion of assault with a deadly weapon, according to Riverside County sheriffâ€™s officials.
The boy is being held at Indio Juvenile Hall.
According to Deputy Armando Munoz, deputies were called to the area of Ramon and Rattler roads to investigate reports of a shooting and found the victim lying in the center median with a non-life-threatening wound.
The man, whose identity was not released, was transported to a hospital for treatment and is expected to make a full recovery.
Munoz said Rancho Mirage High School, 31001 Rattler Road, was close enough to the scene of the shooting that a precautionary lockdown was ordered while deputies and California Highway Patrol officers combed the area, searching for the suspect.
Students were prohibited from leaving their classrooms until about 11:30 a.m., when the order was lifted.
No other injuries were reported in connection with the attack.