After impressing at the Yas Marina post-season test, Sirotkin signed for Williams in 2018, replacing Felipe Massa to partner Lance Stroll and making his Formula One debut at the Australian Grand Prix.

He scored his maiden points finish in Italy, but was dropped by Williams at the end of the season after SMP withdrew his sponsorship due to performance concerns with the FW41.

Having turned 15 years old, Sirotkin graduated to single-seaters, racing in the newly launched Formula Abarth series in Italy for Jenzer Motorsport.

[6] Sirotkin remained in Formula Abarth, and with Jenzer, for a second season in 2011; the series splitting into two separate classifications for European and Italian championship races.

[11] At Valencia, he again started behind points leader Quaife-Hobbs, but this time Sirotkin passed him before the first turn, and eventually scored his first win—again setting fastest lap—becoming the youngest Auto GP winner in the process.

Sirotkin made his Formula Renault 3.5 debut in his home event at the Moscow Raceway, partnering fellow Russian driver Nikolay Martsenko at BVM Target.

He scored his first pole position and won his first Formula Renault 3.5 Series race on his home soil at Moscow Raceway.

Sirotkin participated in tests that took place in Bahrain on 8 April, where he completed 75 laps and covered a distance of over 300 kilometres, recording the 8th fastest time.

Sirotkin made his race weekend debut in free practice at the 2014 Russian Grand Prix where he recorded the 17th fastest time, some four-tenths of a second slower than his more experienced teammate Adrian Sutil.

Sirotkin was unable to secure a contract with Sauber for 2015 because the team completely changed its structure and selected drivers with good financing.

In April 2016, Sirotkin's Formula One chances were revived when it was announced that he would act as a development driver for the Renault Sport F1 Team and would take part in the first free practice session of the Russian Grand Prix.

He took part in the first free practice sessions during the Russian, Spanish, Austrian and Malaysian Grands Prix and received positive feedback from Renault head Cyril Abiteboul.

[35] After the 2017 Abu Dhabi Grand Prix Sirotkin had a half-day test with Williams at the Yas Marina Circuit as the team evaluated potential drivers for the 2018 championship.

[36] In January 2018, he was announced by Williams as their new driver for the 2018 season as the teammate of Lance Stroll, replacing Felipe Massa, who retired from the sport.

[37] Sirotkin qualified 19th for his first Grand Prix in Australia, but his first F1 race was ended shortly after a sandwich bag got into his Williams car brake system.

[41] Prior to the accident he also collided with Sergio Pérez which led to the three-place grid penalty on the start of the Spanish Grand Prix.

[45] The situation with the car remained the same for the triple header (French, Austrian and British Grand Prix), where he was the last man to cross the finish line.

The car was slightly improved for the German Grand Prix, allowing him to repeat the Baku grid position, but in the race he was forced to retire due to an engine oil leak.

[47] While in the Italian Grand Prix, he finished eleventh but was promoted to tenth, scoring his first ever World Championship point after Romain Grosjean was disqualified for technical infringements.

He was forced to make an early pit-stop, and had a long battle with Sergio Pérez, who turned into the Russian driver's car.

In 2020, Sirotkin signed with AF Corse to drive a factory-supported Ferrari 488 GT3 at the GT World Challenge Europe Endurance Cup.