Ryan Nelsen's last game in a QPR shirt will be against Manchester City on January 29 after confirmation he will start his job with Toronto FC on February 1.
The 35-year-old New Zealand international announced his decision to become head coach at the Canadian MLS side on January 8.
Nelsen has been one of the standout performers for Rangers this season and his departure will leave a hole in manager Harry Redknapp's defensive plans.
The defender told Toronto FC TV he had been targeting a senior coaching position for a long time.
He said of his change in roles: "I just love it. It's where my head's been for a few years now. You love everything about football but playing I didn't really enjoy so much as coaching. When that was happening, I knew it was time."
Nelsen has also made the decision to retire from international football, informing New Zealand officials of his desire to focus solely on his new managerial career.
"I spoke with NZF Chairman Frank van Hattum and All Whites coach Ricki Herbert earlier today to personally confirm my decision to retire from international football," Nelsen confirmed.