Christian Horner said his overriding feeling was "shock" as he bid farewell to Red Bull with an emotional speech in front of the team on Wednesday.
Horner, who had spent over the last 20 years with the team, was informed of the decision on Tuesday, but was given the chance to say his goodbyes to his former employees 24 hours later.
The 51-year-old has since been replaced by Laurent Mekies as Red Bull's new team principal.
Horner had been in charge of the team since 2005, their first season in Formula One, and oversaw two periods of dominance in the sport.
He led Red Bull to six constructors' and eight drivers' championships, the latest of which came last year when Max Verstappen claimed his fourth consecutive world title.
But their performance plateaued in the middle of the 2024 season, which saw them miss out on the constructor's title to McLaren, their first since 1998.
And this season, Red Bull find themselves fourth in the team standings, 288 points behind leaders McLaren, with Ferrari and Mercedes also above them.
Verstappen has also dropped off the pace. He finds himself 69 points adrift of championship leader Oscar Piastri, who has won five races so far this season.
No official reason has been given for the decision to replace Horner.
"Yesterday, I was informed by Red Bull that operationally I would no longer be involved with the business or the team moving forward," Horner said as per Sky Sports.
"I will still remain employed by the company, but, operationally the baton will be handed over. It came as a shock to myself.
"I've had a chance to reflect over the last 12 hours and wanted to stand in front of all of you to break this news and to express my gratitude to each and every single member of the team that has given so much during the last 20-and-a-half years.
"When I arrived 20 years ago, there were a few less grey hairs. I walked into a team and did not know what to expect but I was immediately welcomed and we started to build what became a powerhouse in F1.
"Watching and being part of this team has been the biggest privilege of my life."
