[4] He reached his maiden Challenger final at the 2021 Garden Open II in Rome, Italy where he lost to Juan Manuel Cerundolo.

Cobolli qualified for the 2023 BMW Open and defeated Jordan Thompson in the first round and Oscar Otte in the second to reach his first ATP quarterfinal.

He made his Major debut at the 2023 French Open, defeating Mathys Erhard, Lukas Klein and Laurent Lokoli in qualifying.

In the First Round he faced World Number 1 Carlos Alcaraz on Court Suzanne Lenglen and was defeated in straight sets.

[10][11] There, he defeated Dominic Stricker but lost to Arthur Fils and Luca Nardi ans failed to progress to the semifinals.

In February, he reached his second ATP quarterfinal at the 2024 Open Sud de France with wins over two Frenchmen, eighth seed Gaël Monfils and Constant Lestienne.

[16][17][18] At the 2024 Mutua Madrid Open he reached the third round of a Masters for the first time defeating two Chileans, Alejandro Tabilo and 22nd seed Nicolás Jarry.

At his home tournament, the Italian Open, he reached the second round with a win over Maximilian Marterer before losing to Sebastian Korda despite leading with a break in the 3rd set.

At the 2024 Geneva Open he reached his third ATP quarterfinal for the season with wins over Aslan Karatsev and fourth seed Ben Shelton in three sets.

[19] He defeated Alexander Shevchenko in straight sets in the quarter-finals to reach his first ATP semifinal, where he lost to second seed and eventual champion Casper Ruud despite having match point.

The week after, he reached the second round at the 2024 National Bank Open in Montreal on his debut, with a win over 14th seed Félix Auger-Aliassime and moved to a new career-high ranking of world No.

At his next tournament in Cincinnati he recorded the biggest win of his career thus far over 10th seed Tommy Paul, saving three match points.

At the US Open he reached the third round defeating James Duckworth and Zizou Bergs before losing to 5th seed Daniil Medvedev in straight sets.

His following tournament was in Vienna where he defeated Davidovich Fokina for the second time this year, before suffering an injury in the 2nd round against Alex de Minaur.