The Modena-based side lost former manager Eusebio Di Francesco to Roma in June and had been actively searching for an able replacement.
Under Di Francesco, the club finished 12th last term.
The 40-year-old Bucchi, who has previously coached Pescara, Gubbio, Torres and Maceratese, joins from Serie B side Perugia.
A statement from the club read: “U.S Sassuolo Calcio announces that it has entrusted the management of the first team to Mr Cristian Bucchi.
“The Press conference will be held tomorrow, Wednesday June 21, at 12 noon at Modena Golf & Country Club in Colombaro.
“Still tomorrow, June 21, there will also be the presentation of Cristian Bucchi to the Neroverdi fans with a meeting, organised in collaboration with the Amministrazione Comunale di Sassuolo scheduled for 21.00 at the Piazzale Roverella in Sassuolo.
“We invite all fans to attend the evening to give a warm welcome to Cristian Bucchi.”