Joe Manganiello was originally cast as Rip Taggart but left the series in April 2016 due to a 'manageable' preexisting health issue.

About a week after Manganiello's departure, Walton Goggins was cast as his replacement.

Because of the recasting, nearly two full episodes that had already been shot with Manganiello's character had to be re-shot with Walton Goggins.

Christopher Backus had also been cast in the series but left the project to join the show Roadies before Six started shooting.

Season two, produced by the new production company Six 2 North Productions Inc., began filming on July 17, 2017 in Metro Vancouver, around Pemberton, and throughout British Columbia, wrapping on November 23, 2017.

On Rotten Tomatoes, Six holds a 62% approval rating based on 13 reviews with an average score of 6.1/10, with critics noting its well-crafted action despite a familiar narrative.

Metacritic gave the series a score of 54 out of 100 based on 14 critics, indicating 'mixed or average reviews'.

History Channel aired an hour-long special called 'Mission Debrief' on May 23, 2018, recapping season 1 before the show's cancellation was announced that June.