Six Four cast: who's who in the crime drama series

Six Four cast: Kevin McKidd and Vinette Robinson running through a train station
Kevin McKidd and Vinette Robinson lead the cast of Six Four. (Image credit: ITV)

Six Four is the latest ITVX crime drama, based on the Japanese novel by Hideo Yokoyama, which follows a police detective as he tries to find his missing teenage daughter. 

The television adaptation of Six Four is set in Scotland and deals with themes such as police corruption and the criminal underworld, and it looks like it'll be a gripping story as we uncover the truth about why a teen went missing.

There's a great cast attached to the ITVX drama, with familiar faces from the world of film and television playing the roles of police officers, criminals and more, as we begin to unravel a world of lies and corruption.

Here's everything you need to know about the Six Four cast...

Kevin McKidd as Chris O’Neill

Kevin McKidd on the phone in Six Four

Kevin McKidd as Chris O’Neill. (Image credit: ITV)

Chris is a Detective Constable, who finds himself deeply disturbed by the sudden disappearance of his daughter, Olivia. It's even more devastating to learn that he's not her biological father. Despite this bombshell, he loves his wife Michelle deeply, but he also has his own dark secrets.

He's played by Kevin McKidd, who is best known for his roles as Dr. Owen Hunt in the long-running medical drama Grey's Anatomy and as Tommy Mackenzie in Danny Boyle's hit movie Trainspotting. 

Vinette Robinson as Michelle O’Neill

Vinette Robinson descending an escalator in Six Four

Vinette Robinson as Michelle O’Neill. (Image credit: ITV)

Michelle worked as an undercover police officer and met Chris after her cover was compromised and she moved to Scotland for her safety. They quickly fell in love and she has hidden the fact that Olivia is not Chris’ daughter. However, the truth came out in the heat of an argument, and now Michelle is terrified Olivia will fall into the hands of Piers, her biological father and criminal she helped convict.

Vinette Robinson is known for her role as Carly in the tense movie
Boiling Point, and for playing the role of Rosa Parks in an episode of Doctor Who. She has also had roles in BBC's Sherlock and Netflix dystopia Black Mirror.

James Cosmo as Jim Mackie

James Cosmo as Jim Mackie in Six Four, with his arms folded looking down

James Cosmo as Jim Mackie. (Image credit: ITV)

Jim Mackie was once a lawyer working for the Scottish Independence movement and is a former friend and mentor of Justice Minister Robert Wallace. His life was devastated 16 years ago by the sudden disappearance of his daughter, Julie. He is grief-stricken and determined to get justice, as he thinks her death has been covered up.

He's played by James Cosmo, who is best known for his roles as Angus MacLeod in Highlander, and Campbell in Braveheart. He also played Jeor Mormont in the hit HBO series Game of Thrones and Luka Gocharov in season 3 of Prime Video's Jack Ryan.

Andrew Whipp as Phillip O’Neill

Andrew Whipp as Philip in Six Four, wearing police uniform

Andrew Whipp as Phillip O’Neill. (Image credit: ITV)

Philip is the Assistant Chief Constable and Chris’ brother. He's determined to land himself the top job and works closely with Robert Wallace. However, Philip's career is tainted, as he's involved in the cover-up of Julie Mackie's death and has other secrets buried away too.

Andrew Whipp has starred in a number of soaps including Emmerdale, Holby City, and EastEnders, and is best known for his roles as Danny Cairns in Shetland and Brian Fraser in Outlander

Brian McCardie as Bill Martin

Bill Martin in Six Four, wearing a suit and looking serious

Brian McCardie as Bill Martin. (Image credit: ITV)

Bill Martin is one of the original officers who investigated Julie Mackie’s disappearance and was chiefly involved in the cover-up of her supposed kidnapping. He’s now a private security officer for Robert Wallace. He is described as "a ruthless, clandestine figure".

He's played by Brian McCardie, known for his roles as Tommy in BBC's Line of Duty, Dougie Gillman in Jon S. Baird's movie Filth, and Sir Marcus MacRannoch in Outlander.

Six Four airs on ITVX on Thursday, March 30. It will be released on ITV1 in due course. 

Lucy Buglass
Senior Staff Writer

Lucy joined the WhatToWatch.com team in 2021, where she writes series guides for must-watch programmes, reviews and the latest TV news. Originally from Northumberland, she graduated from Oxford Brookes University with a degree in Film Studies and moved to London to begin a career writing about entertainment.

She is a Rotten Tomatoes approved film critic and has a huge passion for cinema. She especially loves horror, thriller and anything crime-related. Her favourite TV programmes include Inside No 9, American Horror Story, Stranger Things and Black Mirror but she is also partial to a quiz show or a bit of Say Yes to the Dress