Williams appointed Mercedes strategy director James Vowles as their new Formula One team boss on Friday following the departure last month of Jost Capito.
Vowles, 43, will join the team on Feb. 20 ahead of testing in Bahrain from Feb 23-25 and the season-opening race at Sakhir on March 5, the Mercedes-powered former champions said in a statement.
"It's an honour to join a team with such an incredibly rich heritage. The team is an icon of our sport, one I greatly respect, and I am very much looking forward to the challenge," said Vowles.
"Mercedes have been hugely supportive on my journey, and we part on excellent terms after over 20 years of working in Brackley."
Vowles has been director of motorsport strategy at Mercedes for the past four years and has played a part in winning nine constructors' championships and 120 races.
He has been in Formula One for 21 years and worked for Mercedes predecessors British American Racing (BAR), Honda and Brawn GP at Brackley.
Brawn GP won the constructors' and drivers' world championships in 2009 with Jenson Button and Vowles has also been involved in six of Lewis Hamilton's seven driver's titles.
"I am grateful for everything (Mercedes boss) Toto (Wolff) and the team have provided, and it has been such a special experience to journey together through failure and success," he added.
"Williams Racing have placed their faith and trust in me, and I will do the same in return. Williams has tremendous potential, and our journey together starts in a matter of weeks."
Matthew Savage, chairman of Williams' U.S.-based private investment owners Dorilton, said Vowles would bring performance to a team who finished last overall in 2022 and have not won a race since 2012.
Williams are nine times constructors' world champions, second only to Ferrari, and also won seven drivers' crowns in their heyday but were last on top with Canadian Jacques Villeneuve in 1997.
"He has been a key part of some of the most impressive feats in the sport over the past 15 years," said Savage of Vowles.
"We believe that the appointment of James reinforces our dedication to ensuring we have energetic, experienced, and strong leadership as we move into the next phase of transforming Williams Racing."
Capito, 64, stepped aside in December after two years in charge, with technical director Francois-Xavier Demaison also leaving.
Dorilton bought Williams from the founding family in August 2020.