"I think this is a really important lesson for young people that your social media footprint will follow you. "I would like to thank everyone that has helped me, both within the party and across the community. I am sorry if I have let you down."
Earlier, Labor leader Bill Shorten addressed new posts that emerged on Friday including one in which Mr Creasey reportedly joked about watching a female friend have sex.
The Australian reports that in the 2012 post Mr Creasey is alleged to have made the comment about a female friend having sex.
After earlier sticking by Mr Creasey, Mr Shorten later on Friday said he’d asked the Victorian Labor Party secretary for a “full briefing” on the matter.
"We want to put an end to this matter one way or another today,” he told reporters.
Mr Creasey has also apologised for sharing a rape joke online when he was 22 years old.
"I'm not going to defend the remarks, they were shocking and stupid. But he's also come forward and said he was 22 at the time, seven years ago," Mr Shorten said earlier on Friday.
"He is mortified as he should be."
Prime Minister Scott Morrison heaped pressure on Mr Shorten after Tasmanian Liberal Jessica Whelan resigned from the party over anti-Muslim posts, saying his stance was different to the Labor leader's.
"I'm puzzled as to why Bill Shorten would want to accept that 'I was just a young man at the time" defence'," Mr Morrison said, earlier.
Coburg High School, where Mr Creasey worked as a teacher before resigning to run in the federal election, issued a statement saying several students, staff and parents had taken offence to the comments.
The comments did not reflect the school’s values, Principal Stewart Milner said.
“The posts were not made when Luke was a teacher here at Coburg High School nor at his previous schools,” he said in a statement.
Who’s running in your electorate? Check out our interactive map