Jarrid Thomas Baldogo, 29, was arrested at his residence in the Westpark area of Irvine around 4:30 p.m.
Investigators said the sexual abuse occurred between February and April of this year.
The underage victim's parents alerted authorities about the abuse on May 8 after they found suspicious text messages sent by Baldogo to their son.
Detectives immediately began an investigation and served a search warrant at the suspect's residence Thursday. Baldogo was shortly arrested.
The suspect's neighbor, Natasha Ulibarri, says she isn't surprised by the allegations. She says she saw a teenage boy coming and ongoing from his apartment several times. Ulibarri says she even approached Baldogo once and asked him if the boy was his son.
"I didn't see people coming other than the kid, that's what's strange," said Ulibarri. "I didn't see girls coming. I didn't see guys coming, I just saw that one boy several times."
Police believe there may be additional victims since Baldogo has been coaching tennis as a private instructor for the past couple of years.
"He's been finding his own clients," said Irvine police Lt. Julie Engen. "We believe he's been advertising somehow on the Internet."
The suspect also worked as an employee of a company providing tennis instruction in the Woodbridge area of Irvine.
The investigation is ongoing as the 29-year-old remains behind bars. Possible victims or anyone with information regarding the sexual abuse were urged to contact Detective Jonathan Sampson at (949) 724-7179.