Jason Humphreys, 39, was arrested at Panania in the western suburbs on Monday evening.
He was charged with 17 offences including aggravated sexual intercourse with a child, sexual intercourse with a child, assault occasioning actual bodily harm and common assault.
Detectives allege Humphreys sexually assaulted the girl on several occasions this month at the house in Lurnea where he rented a room.
They say he also attacked her in his truck last week while travelling from Sydney to Canberra.
The pair met via Snapchat in late 2019.
“This was initiated on social media — the girl did not know this person before that contact,” Detective Superintendent John Kerlatec said.
He said Humphreys befriended the teenager — “a typical 13-year-old girl” — and enticed her to meet him in person before sexually “grooming” her.
He urged young people to be aware of who they could be dealing with online.
“We just can’t make it loud enough,” he said.
“These offences do occur. Not only in NSW but right across the country. It is concerning.” Humphreys’ matter was heard briefly in Bankstown Local Court today.
He didn’t apply for bail and it was formally refused.