Earl Wayne Gann, 56, of Corona was sentenced this week.
A second charge of lewd and lascivious acts was dropped as part of a plea agreement.
On June 15, Gann inappropriately touched the 14-year-old girl during a therapeutic massage at Ontario Christian School, according to a probation report from the San Bernardino County Probation Department.
Later that day, Gann told the girl, "I'm going to be honest with you ... That stuff in the ice room, I liked it," according to the probation report.
He reportedly said, "It's been a long time since I've touched a woman like that and it felt good. We should keep our relationship secret."
Following an exercise session that same day, Gann and the girl went back into the school's training room where he kissed her on her stomach, according to the report.
The girl told a friend, who in turn told a school counselor.
School administrators forwarded a report of the incident to San Bernardino County Child Protective Services.
The agency then notified Ontario police officers.
Gann was arrested on June 26. He pleaded not guilty to the charges the next day.
In September, he pleaded no contest to one count of lewd and lascivious acts and accepted the plea bargain.
In an interview with the probation officer, Gann said he "took the plea so that he could get out of custody sooner, so that he would not have to put his family and others through a trial," according to the report.
Gann, who still denies any wrongdoing in this matter, was sentenced in West Valley Superior Court on Thursday. The girl's family was not present at the hearing, said Deputy District Attorney Karen Schmauss, because they want to put the whole thing behind them.
Gann, who has been in custody since his arrest, received credit for 258 days, meaning he has about 100 days left to his sentence.
But Schmauss said her priority was getting him to register as a sex offender, which should prohibit him from coaching minors again.
"If someone does a background check, he's not going to be allowed to contact kids who are not his own," Schmauss said.
Although Gann has not been charged or convicted of any other offenses, another alleged victim came forward during the recent investigation, officials said.
The now 35-year-old woman said Gann penetrated her with his hand and exposed himself to her when she was 12, according to the probation officer's report.
Gann sent her a letter of apology in which he asked for forgiveness, according to the report. While the woman's parents confronted Gann, no charges were filed.
Gann - a self-employed, licensed roofing contractor - only coached the Ontario Christian soccer team for the past year.
Prior to that, he spent several years coaching in the American Youth Soccer Organization, most recently associated with the Eastvale/Norco AYSO region.
If he had been convicted at trial, Gann was facing a maximum of three years, eight months in prison. His defense attorney, Lee Sonnenberg, declined to comment.