Alex was born in Canberra but raised in Sydney. His father is a physics and astronomy teacher in Sydney, Australia. He graduated in 2002 from the National Institute of Dramatic Art. It was rumored that Bon Scott was O'Loughlin's biological father, however this is false.
O'Loughlin's film career started off in 2004 when he landed his first lead role in the film Oyster Farmer. Continuing his career O'Loughlin appeared in Man-Thing, Feed, and the Australian mini-series The Incredible Journey of Mary Bryant for which he received two acting nominations. O'Loughlin joined the cast of The Shield in 2007 as Detective Kevin Hiatt, the newest member of the strike team.
He left The Shield after he won the lead role on the CBS series Moonlight, where he played private investigator and vampire Mick St. John. The filming of Moonlight was interrupted by the Hollywood writers strike. There was speculation that the series would be dropped but fan pressure prevailed and the show was given 4 extra episodes to try to regain its audience share. However, despite being the highest rated show in its Friday evening slot, consistently achieving over 7 million viewers, CBS did not commission a second season. Fans have started an internet campaign to try to bring back Moonlight, and hopes have been raised and dashed several times. The latest speculation centers around the Sci-Fi channel. If a new series fails to get the green light, there has also been talk around Hollywood of a movie. Either way, the fan reaction to the show has raised O'Loughlin's profile and he is unlikely to be off the screens for long, whether as Mick St. John or a new character.
SCI FI has officially picked up "Moonlight" and will be showing reruns every Friday night starting January 23, 2009 at CBS's original airing time.
O'Loughlin currently stars in the reimagined Hawaii Five-0 series as Lieutenant Commander Steve McGarrett. The series began on September 20th 2010, 42 years to the day that the original had first started. The show has currently aired for four seasons, with a fifth due to premiere in September 2014.
- O'Loughlin was once considered for the role of James Bond. The consideration itself boosted his celebrity status.
- Like Rowlings, O'Loughlin also suffered from OCD as a child.