"It is with a heavy heart that I've decided to take this decision," Henry said in a news release. "The last year has been an extremely difficult one for me personally. Due to the worldwide pandemic, I was unable to see my children.
"Unfortunately due to the ongoing restrictions and the fact that we will have to relocate to the U.S. again for several months will be no different. The separation is too much of a strain for me and my kids. Therefore, it is with much sadness that I must take the decision to return to London and leave CF Montreal."
Henry was named Montreal coach in November 2019 and took over a team that was fresh off a campaign of 12 wins, 17 losses and five draws and had missed the MLS Cup Playoffs for a third consecutive season.
When he was introduced as coach, Henry acknowledged that he fell in love with French-speaking Montreal, a diverse city where he said he hoped to have a long adventure with the club.
In his one season in charge, Henry had a record of eight wins, 13 defeats and two draws, guiding Montreal to the playoffs as well as the CONCACAF Champions League quarterfinals.
"Thierry's departure is unfortunate and premature because this was very promising, but he informed me of his desire to be back with his family because the situation was and remains very difficult for both him and his family," said CF Montreal sporting director Olivier Renard. "I want to thank him, first on a human level because he led the players by example last year by being away from his family, but also from a sporting level and for what we have built together since his arrival. We wanted to elevate this club and we are on the right track. The process of finding a new head coach is already underway and I will be looking for someone who is aligned with the philosophy we have implemented."
In a news conference following the announcement, team president Kevin Gilmore described the reasoning behind Henry's decision to leave.
"Obviously it's taken its toll on Thierry and his children. And he made a difficult decision -- although I keep saying when you make decisions based on family, they're always good decisions - to stay in London, and give up his position as the head coach of the club in order to be close to his family, Gilmore said.
"[Are we] Surprised? Yes, because obviously our plan was one, to bring Thierry here for a long term and, in partnership with [sporting director] Olivier [Renard], to build an identity and the successful franchise we're looking to build," Gilmore added.
"We're not surprised though by the circumstances. Very few people can appreciate how difficult last year was for this club and Canadian clubs in general."
The MLS regular season kicks off in April and Renard said a search for a new head coach was already underway.