Johnson was not found guilty on another charge, but has for a charge of sexual touching after the conclusions of the jury at Bradford Crown Court today.
The ex-England international now faces jail but has been granted bail until his sentencing - which will take place in between two and three weeks.
Victim describes 'hardest' times
After the verdict today, a statement was read on the victim's behalf, who remains unnamed due to her age.
The 15-year-old described the last 12 months as the "hardest year" of her life, with her having had to deal with "so much abuse after [Johnson] claimed his innocence," before he went on to plead guilty last month.
"I was made out to be a liar," she added, explaining that the "assumptions" people made about her were "hard to deal with."
At first, she claimed, meeting her idol was "surreal," but now "what happened in his car has turned [her] life upside down."
She said she feels "used and let down" by the footballer, but is glad that the truth has come out now and that "everyone" can see she was not lying after all.
Johnson facing prison sentence
Speaking after the verdict, the judge said that his initial view of the case is that it warrants a five-year prison sentence, which can range from four to 10 years.
Johnson will find out his fate later this month, with him released on bail for now so he can get his "affairs in order," the judge stated.
He warned the footballer that he "must understand" that there is "a very high probability of a significant custodial sentence," telling him to "say goodbye to [his] daughter," as being sent to prison will stop him from seeing her "for some time."