Has a sister, Jennifer, who is one year younger than he is.
His middle name has been reported as James.
Following the withdrawal of Pierce Brosnan, O'Loughlin was a candidate for the role of James Bond, until the role was recast with Daniel Craig in 2005, in preparation for Casino Royale (2006).
His parents got divorced when he was 2-years-old. He was born in the city of Canberra but grew up in Sydney. From the age of 10 onward, he commuted between the two cities to spend time with both parents.
He did a lot of his own stunt work in Moonlight (2007) and had some training in Kung fu and and Tai chi in order to prepare for his role.