Williams replace struggling Sargeant with Colapinto for rest of season
Colapinto, a 21-year-old Argentinian, will team up with Alex Albon for the first time at this weekend's Italian Grand Prix in Monza.
A member of the Williams driver academy Colapinto moves up to motorsport's fast lane after impressing in F2 this year, with a win at Imola.
His big chance came after Sargeant suffered a terrible weekend at Zandvoort, crashing his heavily upgraded car in third practice for the Dutch Grand Prix on Saturday.
Sargeant gained his sole point for Williams at the US Grand Prix last year, becoming the first American to score in F1 since Mario Andretti three decades before.
A starter of 36 races, he will remain part of the team's set-up.
Williams boss James Vowles acknowledged it was a tough blow for Sargeant.
"To replace a driver mid-season is not a decision we have taken lightly, but we believe this gives Williams the best chance to compete for points over the remainder of the season," he said.
"We have just brought a large upgrade to the car and need to maximise every points-scoring opportunity in a remarkably tight midfield battle."
Sargeant's successor, the first F1 driver from Argentina in 23 years, has already had a taste of F1 life, taking part in first practice at Silverstone before the summer break.
Vowles commented: "Franco is getting a fantastic opportunity to demonstrate what he is capable of across the final nine rounds of the season.
"I know that Franco has great speed and huge potential, and we look forward to seeing what he can do in Formula 1."
Colapinto is itching to show he is worthy of Williams' confidence.
"Coming into F1 mid-season will be an enormous learning curve, but I am up for the challenge, and I'm fully focused on working as hard as I can with Alex and the team to make it a success."
Vowles concluded: "Logan remains a talented driver and we will support him to continue his racing career for the future."
In 2025, Albon will be racing alongside Carlos Sainz, the Spaniard who is joining the team as Lewis Hamilton takes the Spaniard's seat at Ferrari.