Ex-McLaren Formula 1 team manager Dave Redding will officially start at Williams in the same role after the British Grand Prix.
Redding's switch from McLaren to Williams was revealed by Autosport in February, with Williams sporting manager Steve Nielsen moving aside.
Williams had initially planned a handover phase that would leave Redding with "full responsibility for the race team in 2018".
The British team has now confirmed Redding will start on July 17, the Monday after the British GP at Silverstone, with Nielsen leaving Williams two weeks later, on July 31.
"Having been involved in motorsport for 30 years, I know that Williams is a great racing team, and one that I am extremely excited and privileged to be joining," said Redding, who will be responsible for Williams's operational and sporting management.
"I already know and respect many of the team members, and I can't wait to start work at Grove and to be an integral part of an exciting future for the team."
Redding joined McLaren in 2001 as a systems engineer, having previously worked at Jaguar, Stewart and Benetton.
Williams chief technical officer Paddy Lowe said he would build on the work Nielsen did, which included turning the team into F1's benchmark at pitstops.
"Firstly, I must thank Steve for his hard work and dedication since joining Williams in 2014," said Lowe.
"He has done a brilliant job in restructuring the race team and particularly in driving the impressive pitstop performances we have shown in the last 18 months.
"From a personal perspective, it has been a great pleasure to work together since I started here in March.
"We all wish him the very best for the future.
"I am also delighted to welcome Dave to the Williams team.
"I'm sure Dave will fit in well and be able to provide the operational and sporting leadership necessary to not only maintain our current high standards, but to build even further on all aspects of our race team performance in the future."