He was first included in a matchday squad for their Coppa Italia fourth-round game on 28 November 2012, remaining unused in a 3–1 loss to Atalanta at the Stadio Atleti Azzurri d'Italia.

[21] He returned in Sassuolo in July 2016 ahead of 2016–17 season, making his Serie A debut by playing full 90 minutes in the opening championship match against Palermo, which ended in a 1–0 away win.

[24] Sensi was a key player in the 2018–19 season under manager Roberto De Zerbi, making 30 appearances between league and cup, netting twice in the process.

[25] On 2 July 2019, Inter Milan officially announced that Stefano Sensi had been signed from Sassuolo on an initial paid loan deal, with an option to buy at the end of the season.

[26] Sensi made his club debut on 26 August in a 4–0 home win against Lecce, in Inter's opening match of the 2019–20 Serie A season; he marked the occasion by scoring a goal, but later came off in the second half for Roberto Gagliardini.

[27][28][29] Sensi made his Champions League debut on 17 September in a 1–1 home draw against Slavia Prague; he contributed to Inter's injury-time equaliser, as his free kick struck the cross-bar, and was subsequently turned in by Nicolò Barella to tie the game.

[37] After one season at Inter, where he won the 2023–24 Serie A title, Sensi returned to Monza on a permanent transfer on 8 August 2024, signing a one-year contract until 30 June 2025.

[4] On 20 November 2018, he made his debut with the Italy senior team, playing as a starter in a 1–0 friendly victory over the United States, held in Genk.

He often acts as a deep-lying playmaker in front of the back-line, due to his ball control, range of distribution, and long passing ability with both feet in spite of being naturally right-footed, which allows him to create chances for teammates; he is also capable of playing in several other midfield and offensive positions, and has been deployed as a winger, as a mezzala, or as a supporting forward.

In spite of his slender build, which makes him ineffective at winning more physical challenges for the ball, he is also effective defensively due to his tactical intelligence and interpretation of space.