His victim claimed her friends saw the "sex counter" online and were upset for her.
Campbell, 22, from Hampton, pleaded guilty today to two counts of sexual penetration of a child under the age of 16.
The maximum penalty is 10 years' jail.
When the victim turned 16, Campbell joked, "Now you're legal".
He had been 17 at the time of the offending.
Ms DiPietrantonio said Campbell had become friends with the victim on the MySpace website.
They had sex for the first time after going to the movies in the city and returning to Campbell's home where he lived with his mother.
They had dinner together before Campbell took the girl to his bedroom and had sex with her, telling her, "It's OK, I've got protection."
The girl was a virgin and told Campbell she had never done anything like this before.
After they had had sex, Campbell ignored the girl and went into another room to play on his computer while the victim stayed in his bedroom.
When they had sex another time and the girl told him she was worried about getting pregnant, Campbell snapped at her and again went into the next room to play on his computer.
The relationship ended in February 2009 when Campbell told the girl he was tired of her.
Ms DiPietrantonio said an aggravating feature of Campbell's offending was that he did not use a condom on one occasion.
Reading from her victim impact statement, the girl, now aged 19, said she had been a loving, trusting person until she met Campbell.
She said she felt violated and believed Campbell had exploited her trusting nature and vulnerability.
"I was only a child," she said. "I will never be able to get that happy, loving innocent girl back and that is the worst feeling of all."
The court heard the victim now suffers from post-traumatic stress disorder, panic attacks, chronic insomnia, and often cries for no reason.
She has nightmares about what she calls "the crime" and believes it will take her years to heal.
Judge Richard Maidment said Campbell had behaved in a thoroughly boorish, unpleasant and disrespectful manner to the victim.
The judge said Campbell knew going on to his computer after having sexual intercourse was not an appropriate way of behaving.
He said Campbell's conduct had been deliberate to "show a degree of power and contempt" for the victim.
"It seems to me he can't excuse himself from that type of behaviour ... There is an element here of exploitation."
The judge said Campbell's use of a "sex counter" at the time did not suggest there was any remorse.
Defence lawyer Sharon Lacy said it was important to note Campbell had been 17 and a child at the time of his offending.
Ms Lacy said the "sex counter" had been stupid and juvenile but Campbell claimed it was on a password-protected website.
"Sadly it's not so unusual for young males to record their sexual accomplishments in some fashion," she said.
Judge Maidment placed Campbell on a 12-month community corrections order without conviction and ordered he perform 70 hours of unpaid community work.
The judge said there was nothing to suggest Campbell would reoffend or was a risk to other vulnerable women.
Campbell had no prior convictions and good prospects of staying out of trouble and leading a worthwhile life.
"It is clear when young offenders are concerned, rehabilitation must be a significant factor in the sentencing process," the judge said.